In a Malibu beach house, two very different men and one growing boy create a surrogate family unit that promises to make each one of them a better man.
After falling off the roof whilst fixing Charlie's TV and badly injuring himself, Alan needs someone to look after Jake. Charlie offers but is pushed to his limits by Jake's rudeness and persuading behaviour.
Jake gets suspended from school after drawing an offensive picture of a girl in his class that has large breasts. Meanwhile, Charlie is asked to watch over Alan's chiropractic office after pulling an all-nighter.
Charlie finds out that Alan and Judith have begun to date again.
Berta causes tension between Charlie and Alan when she temporarily moves in with them.
Charlie learns he can't be in a long-lasting relationship because of unresolved issues he has with his mother. Jake asks Charlie for advice about a girl at school.
Ignoring Alan's warnings, Charlie continues to date Isabella until she threatens to put a curse on his manhood.
Charlie wakes up with Rose the morning after her birthday party. Her irate father comes to ask Charlie about what the future holds for him and Rose but the unexpected happens when Evelyn shows up.
Charlie tricks Jake into taking ballet lessons so he can get close to the gorgeous instructor.
One of Charlie's elderly neighbours tries to seduce Alan, while Charlie tries to stop Jake from giving money to a televangelist.
Charlie helps Alan with his obsession of always having to get approval from the women in his life.
Alan starts dating a woman with a Martha Stewart complex. Before long she's running the house with an obsession for perfection.
Charlie sees a therapist to learn how to deal with Alan's emotional insecurities.
Charlie finds himself in a relationship that is not based on sex.
Charlie arranges a romantic date with Mia in the hopes of consummating their relationship whilst Alan begins to date Charlie's most recent ex-girlfriend.
Charlie has trouble keeping up with Mia's healthy lifestyle, so he begins to sneak beers, cigars and burgers behind her back. When Mia finds out, Charlie has to decide if he is truly in love with her or just whipped.
Alan has trouble deciding if he should bring his younger girlfriend to Jake's birthday party to meet his mum and his ex-wife. Rose tries to get her boyfriend to act more like Charlie.
Charlie is nominated for an advertising award but decides to boycott it because his arch nemesis always wins. Rose is having relationship problems with Gordon and seeks help from Charlie.
Alan starts to have financial problems when he starts paying for his girlfriend's bills, so Charlie tries to get him to break up with her. Meanwhile, Judith is after Alan because he's late in paying his alimony check.
Charlie is surprised to find out that Kandi has been living with them for the last three weeks.
Alan tries to win Kandi back. Meanwhile, Charlie starts to sleep with her mum, Mandi, and Judith gets set up with her father, Andy.
Jake's teacher has a meeting with Alan and Judith to discuss the lack of interest Jake has at school. Alan starts to fall for Francine's intellect whilst Charlie helps Jake audition for his school musical.
A girl from Jake's school invites him to his first boy-girl party. Charlie and Alan help him get ready for it by giving advice which leads to them getting nostalgic remembering their first boy-girl party.
Mia comes back to town with her dance troupe and invites Charlie to her performance. When they meet, Mia explains she wants some of Charlie's sperm to which Charlie responds by asking Mia for something in return.
Charlie and Mia start making their wedding arrangements, however, things begin to fall apart when their two families meet. Eventually they decide on a small ceremony in Las Vegas.
Jake moves to Judith and Herb's when he learns Alan is dating the mum of his friend Eldridge. Meanwhile, Charlie tries to cut back on his alcohol intake.
Charlie gets creative in his efforts to force Alan to accept Lyndsey's offer to move in with her.
Though he accepted Lyndsey's offer to move in, Alan continues to use Charlie's beach house to have sex with Melissa.
Charlie gets even more unwanted houseguests after Alan burns down Lyndsey's home.
While Charlie's off getting plastic surgery, Alan takes advantage and pretends to be him at a bar.
Charlie finds himself out of his comfort zone when he learns his date is four years older than he is. Meanwhile, Alan goes on a self-pleasuring binge to use up soon-to-expire ED pills.
Charlie's newest girlfriend can deal with all the craziness in his life, except for Rose's stalking.
When a drunken Charlie ruins Jake's date, Jake retaliates by convincing Alan to hold a birthday party for Evelyn at the house. Russell the pharmacist is subsequently invited when he and Evelyn appear to hit it off.
Charlie is thrilled with the fabulous job Berta's temporary replacement does and Alan thinks Lyndsey's ex-husband is threatening him.
When Charlie's ex-girlfriend Courtney is released from prison he treats her to the good life despite her having been in prison for conning him. However, Alan is concerned that she's using him all over again.
Alan goes to great lengths to be able to get Lyndsey a nice birthday present.
Charlie pays a visit to Dr. Freeman to help deal with breaking up with Courtney.
Alan lets his paranoid suspicions get the better of him when Charlie and Lyndsey start being more friendly to each other.
Obsessed and believing her to be married, Charlie starts stalking Rose. Meanwhile, Alan grows concerned when Jake and Eldridge start videotaping stupid and extremely dangerous stunts.
Rose keeps 'cheating' with Charlie. Alan's plea to family for money, to advertise his chiropractic office, quickly devolves into a Ponzi scheme.
Rose and Alan discover each other's secrets. Meanwhile, Charlie's desperate to get some time alone with Rose.
Walden reprioritises his life.
Alan gets offended when Walden asks him to sign a pre-nup.
Walden and Alan pretend to be a loving couple for the adoption.
Walden and Alan meet a birth mother who is considering them.
Walden decides to foster a six-year-old named Louis.
Alan breaks Walden's rules to appear cool for Louis.
Walden's attracted to a mom at the kids' gym.
Walden and Alan try to convince Louis that Santa's real.
Herb asks Alan if he can go on a date with Lyndsey.
Walden risks losing Louis when his secret with Alan gets out.
Walden joins a group for adoptive fathers - without Alan.
Alan breaks up with the social worker to be with Lyndsey.
Alan hesitates when Lyndsey asks him to move in with her.
Walden offers Alan a divorce gift of his choice.
Charlie Harper is alive. Or is he? Find out in the two-part finale.
Charlie must make a difficult decision about his future as to which woman he wants to spend his life with, Chelsea or Mia. Meanwhile, Charlie also grows wary that Melissa has slowly moved into the house.
Girls rule the roost after Charlie consents to Chelsea's desire for Alan's girlfriend, Melissa, to move in with them.
Alan cares for Judith's child and his ex-mother-in-law. Elsewhere, Charlie backing over a cat provides Jake with a chance to blackmail him.
Alan starts working for Evelyn whilst Charlie tries to close the rift between Chelsea and Jake.
Public humiliation in the form of Charlie and Alan bickering at an ice cream parlour has learner driver Jake refusing to stay at the beach house anymore.
Alan's advice to Chelsea to get breast-reduction surgery is not met with enthusiasm by Charlie, who kicks him out. However, staying with Evelyn has its own challenges.
Having set a wedding date with Chelsea, Charlie and Alan go to a bar only to awaken in the morning to find themselves in bed with a stranger.
Chelsea's gorgeous college roommate stays at the house to recover from a breakup but it would seem everyone at the house wants a piece of her.
Alan attempts to solve thinning hair in cheapskate fashion before heading out on dates. Chelsea reveals Charlie hasn't been pleasing her as much as he thinks he has.
Charlie broaches the subject of a pre-nup and is left stunned to discover Chelsea has just as much need for one as he does.
Charlie helps Jake cheat on his girlfriend while she's away for the holidays and Evelyn brings a television producer to Charlie's Christmas dinner.
Jake hopes to win back Celeste by writing her love songs and Judith tries to quash Alan and Herb's new friendship.
Charlie gets a colonoscopy to avoid visiting Chelsea's parents but she turns the tables by getting them to fly out to Malibu for a visit.
Alan suspects a widowed lawyer, who represented him following his arrest for slugging a guy at a bar when he came on to his date, is interested in Chelsea and suggests Charlie do something about it.
Chelsea is put off by Charlie's jealousy towards her relationship with Brad and he vows to become the better man he says she deserves.
Crushed over his break-up with Chelsea, Charlie goes missing and comes back to Malibu married.
Charlie and Chelsea's break-up doesn't stop them from having a post-breakup one-night stand.
Charlie runs into Chelsea's old friend Gail. Alan learns he's able to please a new female chiropractic patient just by working on her lower back.
Alan is torn between the bad influence of Jake's new friend and the hotness of his mother. Charlie has troubles writing the theme for a new TV show.
Alan plans an intimate night at a hotel with Lyndsay, but her "time of the month" gets in the way.
Alan tries to bond with Jake during a trip of their own to Sacramento to pick up a clock he's inherited.
Charlie is miffed over Alan's planned attendance of Chelsea's birthday party and suffers the indignity of having Jake chauffer him around following a license suspension.
Charlie's long-lost daughter Jenny shows up.
Jenny moves in with Evelyn.
Walden and Alan think it may be time for Berta to retire.
Walden starts partying with Jenny and her hot friends.
Alan befriends Lyndsey's boyfriend.
Alan asks Walden to set him up on a date with Lynda Carter.
Lyndsey's jealousy ruins Alan's date with a beautiful woman.
Alan and Lyndsey's illicit affair puts Walden in danger.
Walden's date with an accident-prone model won't end.
Walden helps Jenny get a second date with a one-night stand.
Walden joins his beautiful former employee on a new project.
Alan lets Lyndsey's boyfriend Larry set him up on a date.
Walden and Alan throw Marty a bachelor party with old friends.
Walden sets out to prove that he's a man's man.
Alan makes Lyndsey choose between him or Larry.
Walden suspects his new girlfriend is cheating on him.
Lyndsey discovers that Alan is sleeping with Larry's sister.
Walden's ex-girlfriend invites him to her boutique opening.
Walden reconnects with Kate and is sure she's "The One" - that is, until he meets Vivian, a beautiful, free-spirited world traveller who shows up on his doorstep.
Alan stumbles upon a money-making opportunity.
Gretchen insists that Alan confess his identity to Larry.
Alan confesses his true identity.
Walden's proposal on Zoey's birthday does not go as planned. Jake adjusts to life in the military and Alan is on edge because any permanent relationship between Walden and Zoey will lead to his eviction from the house.
Shortly after his break up with Zoey, Walden has a breakdown & becomes irritable. After a slight intervention, Walden gets over it & gets even with Zoey by getting her daughter a large slobbering dog for her birthday.
Alan and Lyndsey decide to progress their relationship further by having a pair of threesomes. The first one will involve Walden, the second one a woman of Alan's choice.
Missi, an old family friend comes to visit for a week and develops a relationship with Jake who is home on leave from the Army. When Jake comes to return to base though, Missi reveals she already has a boyfriend.
Walden starts dating Rose. This news shocks Alan and he tries to warn Walden about Rose, describing her tactics and history with Charlie, but Walden disregards them as Rose explained everything to him.
Walden asks Rose to move in so they can spend more time together. The next day, however, Walden gets a call from Zoey. They meet and Zoey confesses she still loves him, which forces Walden into making a decision.
Walden hires an actress to play the part of his girlfriend and ends up falling for her. Meanwhile, Jake and Missi plan a rendezvous which doesn't go well when Alan is informed that Jake went AWOL from the Army.
Lyndsey asks Alan for a commitment, which he doesn't take lightly. Walden is picked up by a rich older woman, who sees him as a poverty-stricken love toy, and she takes him back to her place and seduces him.
Alan finds himself in a bind when his beautiful ex-wife makes a pass at him. However, being in a committed relationship with Lyndsey, Alan tries to do the right thing by turning down Kandi and telling Lyndsey. Meanwhile, Walden helps Berta celebrate her birthday.
Tired of dating or even meeting women who are only interested in his fortune, Walden decides to create an online persona as a poor schlub named Sam Wilson who is very much like Alan Harper (no job, no prospects, no charm). Then he meets Kate, a wannabe fashion designer.
Still pretending to be the poverty-stricken "Sam Wilson", Walden spends Christmas with Kate. Meanwhile, Walden & Billy close a deal to sell their electronic suitcase for $1.2 billion. Elsewhere, Alan's Christmas goes south when all his loved ones have other commitments.
Walden wants to invest in his girlfriend Kate's fashion career, without her discovering that he is billionaire Walden Schmidt rather than broke "Sam Wilson", as he's led her to believe. What is more, the stress of the deception is beginning to affect Walden's health.
Fed up with his double-life and feeling that Kate might be the one, Walden decides he should throw away his "Sam Wilson" alias and confess to who he really is. Kate's in New York at a fashion show, so Walden, accompanied by Alan, set off to tell her the truth in person.
Lyndsey's miffed that she doesn't have a key to the beach house. Meanwhile, Walden, Alan, Billy and Herb share stories about women.
Jake brings home his 36-year-old girlfriend Tammy but Alan becomes concerned about her and Jake due to her job as a tattoo artist, her kids and time spent in prison.
Valentine's day is approaching and Alan wants to make it special for Lyndsey. Unfortunately, his plans go awry at the last minute. Kate is back in town and wants to meet up with Walden but can he convince her to take him back?
Walden attends a singles mixer with friends from high school and runs into Bridget. Alan gets worried when they begin talking about getting back together.
Alan accidentally starts a fire in the kitchen while making toast, resulting in a power outage and embarrassing Walden in front of his date. Alan tries to make it up to Walden but ends up moving out and moving in with a lonely Herb.
Walden and Alan try to cheer up a lonely Herb, but end up living it up a little too large.
When Jake cheats on his girlfriend Tammy with her 18-year-old daughter, Ashley, Alan and Walden get caught in the crossfire.
Alan's world spirals downward when Lyndsey decides their relationship is over. Meanwhile, Walden looks for a solution to free himself from being the sole person in Alan's life.
With Alan still depressed over his breakup with Lindsey, Walden sends him off to get a complete makeover. Even with his new weird look, Alan manages to hook up with a dim-witted blonde. She takes him home, where Alan discovers she has a 92-year old comatose husband.
Walden has a dilemma when he finds he's more attracted to the grandmother of a beautiful but ditzy young woman than the woman herself. Also, Jake reveals he is being transferred to Japan so Alan decides a road trip is on order.
Alan learns that Charlie belongs to an exclusive men's group, and he begs his brother to let him join.
Judith is dating Jake's paediatrician and Alan is upset until Charlie points out that if she remarries, his alimony payments will end.
Charlie tries to save Jake from school suspension for giving his teacher the finger by romancing her, but his several attempts fail every time.
Evelyn borrows Charlie's car to help her impress a Saudi prince, because she wants to sell him real estate. When Charlie gets the car back, he discovers his mother's bra in the backseat. When he finds out why it's there he decides to trade in his car.
Charlie meets his match when he falls for a woman who is better at playing hard to get than he is.
Alan denies having shoplifted a toy as a child and fears he has a dark side, until Charlie admits he planted the toy on Alan to stay out of trouble himself.
Charlie and Alan hire Berta's sister to cater a party their mother has conned them into throwing for her.
Alan meets a woman named Nancy at a grocery store, who fulfils every single one of his desires, forcing Charlie to take care of Jake. After knowing Nancy for a few days Alan decides to ask her to marry him, prompting Charlie to try and talk him out of it.
When Charlie leaves the house to avoid a date that he can't stand, he ends up at a coffee shop where he meets his old girlfriend Lisa, and finds out that she broke up with her husband. Now he must try to convince Lisa that he's okay with her having a child.
Charlie tries to get Jake's approval on a theme song that he is hired to write for a television show, which is based on a comic book that Jake is a fan of. Alan finds out more about Rose, including how smart she is, when he spends more time with her.
After getting unusually turned down at a bar, Charlie learns that a website has been made dedicated to exposing his lifestyle. Charlie sets out to find who created the site, making amends to all those he stood up along the way.
Alan is jealous of Charlie when an old classmate, who's now a beautiful woman, seems to be more interested in Charlie.
After an earthquake hits, Judith's house is damaged and she needs a place to stay. So Alan decides to invite her to stay with him and Charlie, without getting Charlie's permission. Alan becomes jealous when Judith goes on a date, and so asks Charlie to find him a date.
The brothers throw their mother out after she insults the way Alan is raising Jake. To get their attention she ends up in the hospital. When Alan and Charlie show up at the hospital they aren't sure if she's faking and try to call her bluff.
Alan starts to worry about a medical procedure that he is facing, and to get his mind off it, Charlie suggests they go to Las Vegas.
When Judith decides to take a vacation, the brothers have to take care of Jake during the week. When Alan finds out that he has to go to the I.R.S. because they're auditing him, he forces Charlie to take care of Jake, and Charlie doesn't do any better then Alan.
After Charlie has back pain, Alan decides to take him to the hospital. Whilst there Charlie can't stop hitting on the doctor who is examining him. Berta is feed up with Jake's inability to use the bathroom properly, so she decides to make him clean it until he learns.
Charlie is invited to a party hosted by a gay ad-executive named Eric, so Charlie asks Alan to pretend that he's his life partner. While at the party, Charlie meets Eric's ex-wife Pamela and tries to sleep with her without Eric finding out.
After Charlie takes Alan to an eye doctor, they end up at cafe where they bump into Charlie's ex-girlfriend, Sherri. Alan shows an interest in Sherri and decides to ask her out. The problem is that Alan can't get over Sherri's relationship with Charlie.
Rose tries to help the brothers sort out their feelings when Charlie and Alan take their personal frustrations out on each other.
Evelyn learns that her second husband, Harry, has died. They all attend the funeral, including Jake who is excited at the opportunity of seeing a "dead guy". Charlie is excited by the opportunity of a newly single widow, and Alan is just happy to pay his respects.
Evelyn buys Alan a new sports car causing Charlie to claim that his brother has sold his soul to the Devil. The next day, Evelyn extracts payment by insisting that Alan go on a blind, double date with her, her new beau and his daughter.
Evelyn demands Jake spend a night at her place when she finds out he spent Spring Break with Judith's parents. Neither Alan nor Charlie are keen on the idea, but going to a bar after dropping off Jake quickly erases their concerns.
Charlie unknowingly sleeps with an older man's trophy wife while Jake has to read a paper to his class.
Charlie returns to his bachelor lifestyle after Alan moves out of the house whilst Alan suffers a breakdown after his divorce from Kandi.
Charlie finally tells Alan the truth about why he did not marry Mia and they both have to deal with a noisy neighbour.
Charlie tries to surf to impress Dottie, a beautiful woman he just met, but after he nearly drowns he's convinced he saw his late father.
Alan tries to hire his ex-wife's lawyer to help him win custody over the dog he and Kandi shared.
Alan is overjoyed by the prospect of Judith remarrying as he would no longer have to pay alimony. When it looks like the marriage might derail due to Jake's dislike of his mother's fiancé, Alan asks Charlie for help.
Charlie dates a woman whose personality and life are like his mother's.
Berta drags Charlie with her when she confronts the father of her pregnant daughter's baby. Meanwhile, Alan reveals a secret fetish.
Alan suffers about of insomnia and a visit to his psychiatrist reveals the cause of Alan's sleepless nights is his jealousy towards Charlie and his own inability to glide through life.
Charlie gets tired of Alan's mooching and reaches the breaking point during the brothers' double date. Meanwhile, Jake is left home alone for the first time.
Worrying Charlie may get rid of one of them, Berta and Lydia fight over him. Meanwhile, Kandi does everything she can to stop Alan from selling their condo.
Charlie's friends and family put a crimp in his plan for a romantic Christmas Eve date. When Evelyn sees who the date is, she goes to great lengths to force a wedge between them.
Berta discovers that Alan has been dating her daughter Naomi.
Jake shares that he has heard his mother having sex with her fiancé, Herb; a revelation that brings up a repressed memory for Charlie which leads him to seek help from Rose.
Charlie sets Alan up with their new neighbour but gets jealous when the two form a bond.
Rose is moving to London and Charlie is surprised by his reaction to the news. Alan lies to a woman he met online.
Charlie's young, hot girlfriend takes him to a new club. She invites Alan to meet one of her friends but the men are shocked to learn they are considered as being old.
Evelyn tells the men how she feels about there being no mourners at her friend's funeral and they reply it could be the case at hers. Evelyn tries to prove them wrong by introducing them to a couple she helped.
Alan tries to bond with Jake when he realises his childhood is almost over whilst Kandi pursues a career in acting.
Alan is overjoyed at the prospect of giving Judith her last alimony check. Charlie decides to go along for the ride and meets Herb's sister Myra, and the pair end up bonding over their dislike for Judith.
Alan looks forward to Judith's wedding while Charlie and Myra continue their romance.
Alan and Charlie re-examine their sexual identities after Alan befriends Greg, a gay man. Meanwhile, Jake has a crush on Greg's daughter.
Alan asks Charlie to help Jake with his book report so he can take the time to go to the DMV. Charlie agrees and then decides he wants to go to the race track and takes Jake with him.
Charlie is shocked when the handyman working on his house beats him for Chloe's affections and Alan has no sympathy for Charlie's distress.
Evelyn gets a new boyfriend, Teddy, who bonds with Alan and Charlie by taking them to Las Vegas. Meanwhile, they both confront their feelings about their mother dating and the men coming in and out of their lives.
Charlie's life turns upside down when his brother and nephew move in. At the supermarket, Charlie discovers he can use 10-year-old Jake to attract women.
Unsure how to properly discipline Jake, Charlie ignores him after the child 'forgets' to stop feeding the seagulls and leaves the door open, allowing the gaggle of birds to enter the house. Meanwhile, Alan gets a surprise from Judith when he goes to fix her sprinklers.
When Alan's attempt to provide Jake with a fun-filled weekend backfires, Charlie tries to console his brother by taking him to a local bar and getting Alan totally inebriated. As Alan and Charlie travel home, their cab driver offers them some unsolicited therapy.
When Charlie's longtime cleaning lady, Berta, quits her job, Charlie quickly realises he can't function without her and sends Alan to lure her back. Meanwhile, Alan places Charlie in charge of getting Jake ready for Judith, who is coming to take her son out for dinner.
After a drunken night in Las Vegas, Charlie reluctantly attends one of Jake's soccer games and soon discovers the advantages of going to these matches. The players' mothers are quite attractive, and Charlie makes a date with a particularly sexy soccer mom.
Charlie rethinks the way he treats women when he, Alan and Jake are forced to cheer up a pitiful Evelyn after her boyfriend terminates their relationship. Meanwhile, Charlie teaches Jake some valuable lessons about screening calls from women, but the lesson backfires.
Charlie's friend Cindy frequently showers at his house after surfing. When Jake sees a butterfly tattoo on Cindy's partially nude behind and later draws a picture of it in class, Judith gets angry and talks to Alan and Charlie about letting her son see half naked women.
When Alan and Judith argue during a rehearsal of a play that Jake and his classmates are rehearsing, Charlie is forced to handle a roomful of fourth graders alone. The kids think Charlie is a loser until they realise he wrote the "Maple Loops" cereal jingle.
Charlie likes his new girlfriend, Wendy, but becomes concerned when Jake forms a friendship with her. When Wendy charms Evelyn as well, Charlie worries that Wendy is expecting more from the relationship and ends it. When Jake gets mad at him, Charlie learns a lesson.
When Charlie finds out that his favourite ex-girlfriend, Lisa, is getting married, he desperately tries to prove to her that he has become a better family man than her fiancé, despite his inability to commit to her. But Charlie can only carry on the charade for so long.
Charlie and Jake convince Alan to get a makeover when it appears Judith is moving forward since the breakup, sporting a new hairdo and new date. But when Charlie takes Alan shopping, the brothers clash over what image is right for him.
When Charlie's cleaning woman, Berta, brings her sexy and rebellious 16-year-old daughter, Prudence, to Charlie's house, Jake develops a childish infatuation with her ... and Charlie and Alan try to restrain their interest in the flirtatious minor as well.
Desperate to get a date, Charlie volunteers Alan to escort the woman's sister, turning the date into a foursome. Charlie tries to speed Alan's recuperation from a cold, but when Charlie gets ill and Alan discovers how attractive the sister is, their roles reverse.
When Charlie learns that his credit rating is ruined, and his debts are all overdue, he discovers that his accountant, Stan, is completely inept. At Alan's urging, Charlie tries to reduce his spending habits, but he has a difficult time giving up his luxuries.
Charlie and Alan find Frankie, a sexy but seemingly crazy woman, hitting a car with a baseball bat. Charlie brings Frankie back to his Malibu home but the two brothers, both competing for her attention, are taken aback by a secret that she's been hiding.
Frankie explains why she's in hiding with her 8-year-old daughter, Joanie. Both of the men are romantically interested in Frankie, and she reciprocates with one of the brothers. And Joanie likes Jake, who is completely disinterested in her.
Alan offends Charlie by choosing their crazy cousins as Jake's guardians. Later, as Charlie and Jake play basketball, Jake falls, hitting his head. Charlie rushes him to the emergency room and finds that his charm with women doesn't work with the admitting nurse.
Charlie agrees to meet with a former girlfriend who ended their relationship years earlier, leaving Charlie devastated. But Charlie's in for a huge surprise when he discovers that she is now a he, and he, Bill, wants to be Charlie's friend.
Judith's sinister-but-sexy sister, Liz, plans to attend Jake's 11th birthday party. Alan asks Charlie to behave. But when Liz arrives, she ignores Charlie and flirts with Alan instead. Liz proceeds to cause a commotion between her sister and her ex-brother-in-law.
Jake becomes a brooding musician when he continuously plays "Smoke on the Water" on his guitar with an ever-present grumpy attitude. Finally, Judith convinces Alan that Jake needs professional assistance, and they enlist the help of Dr. Linda Freeman.
Charlie and Laura, Alan's divorce attorney, begin a relationship. Laura doesn't care that he dates other women, but she does have one request: Charlie must be available for her whenever she wants him. Charlie loves the idea, until Laura takes advantage of the situation.
Alan succumbs to Judith's demand that they take Jake to therapy every week but he doesn't realise that he, too, is having issues ... with sleepwalking. Evelyn hints to Charlie that Alan used to sleepwalk as a child, leading Charlie to come up with a clever new solution.
When Jake imitates one of Charlie's sexist remarks in front of Judith's support group, the women decide that Charlie's home is an unfit environment for the child. Charlie must cajole the support group in order to win his nephew back.
One of Charlie's many women fears she's pregnant, and Charlie is relieved when the lady finds out she's not. When Alan realises that this is not Charlie's first pregnancy scare, he suggests a permanent solution for Charlie ... a vasectomy.
After saying goodbye to the late Charlie Harper, Alan meets Walden Schmidt (Ashton Kutcher), a broken-hearted billionaire.
Walden has Alan come along for the ride when he tries to get his ex-wife Bridget to take him back.
Walden hopes to start the process of winning back Bridget by taking her to dinner and seeks Alan's advice. Meanwhile, Jake gets ideas in his head when he learns Walden is a high school drop-out.
Alan encounters a chance to reconcile with Lyndsey while Walden seeks to move on from Bridget.
Alan isn't thrilled when he learns of Lyndsey's past so Walden hosts an impromptu party to lift his spirits.
Depressed after receiving his divorce papers, Walden cheers up when he meets a woman who looks very similar to Bridget.
Walden hires Evelyn as his interior designer but Alan fears she may have ulterior motives. Jake crushes on his chemistry tutor, who in turn has a crush on Walden, and Alan can't stop reading Charlie's old journal.
When Walden sells Charlie's piano, Alan goes off the deep end and starts channelling his inner Charlie.
After being released from the mental hospital, Alan is faced with a number of shocking events that test his mental stability.
As Walden hopes to put Bridget in the past and dips back into the world of dating, Alan hopes a pawn shop will be the solution to his financial woes.
Walden hopes to move things forward with Zoey but Bridget's reappearance complicates matters.
Walden's mother visits, dropping a secret about him as well as leaving Alan smitten.
Walden needs Alan and Zoey to help when Bridget and his mother look to wrest away control of his company.
Zoey wants Walden to take on a more clean-cut look. Meanwhile, Alan and Lyndsey reconnect.
When Walden feels Zoey is a bit stiff in the bedroom, Berta suggests a few of her marijuana brownies might loosen her up a bit.
Alan and Walden have to deal with Zoey and Lyndsey's antagonism towards each other when a storm traps them all at the beach house.
Walden's miffed that Zoey didn't reciprocate after he blurted out "I love you" when his jet hit violent turbulence. Alan thinks Lyndsey is drinking too much.
Walden's former business partner shows up, looking to patch the rift between them.
When Lyndsey's mother comes for a visit, Alan suggests she meets Evelyn. Walden is stuck hearing out iPhone app ideas from Jake and Eldridge.
Walden knows Zoey won't be thrilled to learn Bridget is a partner in his new venture with Billy. Meanwhile, Alan and Lyndsey try to cope with their mothers dating each other and deal with Eldridge and Jake's questions.
When Zoey and Ava move in, Walden finds out if his commitment is up to the test. Meanwhile, Alan has his own challenges when he moves in with Lyndsey.
After suffering a minor heart attack, Alan is visited by Charlie's ghost while in the hospital.
Zoey suspects Alan doesn't really deserve all the love and attention he's getting following his release from the hospital.
Having graduated high school, Jake and Eldridge face new urgency to face their adult lives.
Jake is getting ready to advance to junior high but his dad & uncle's scary stories might end his academic career a bit early. Alan & Charlie take him school shopping and find themselves in trouble, both then & later.
Charlie ends up having to go to one of Evelyn's firm get togethers but the event ends up giving the two a friendship. However, Evelyn is one step ahead of Charlie when he becomes interested in one of her clients.
Alan convinces Charlie that he needs to date more respectable women and sets him up with a judge called Linda. The two double date but things don't go too well.
Charlie & Linda get closer to consummating their relationship but Charlie has trouble focusing when he begins to see Rose's face everywhere he turns. Charlie ends up flying to London to find out if Rose is still there.
Charlie discovers that he's good with kids while babysitting Linda's four-year-old son Brandon. Meanwhile, the extreme financial hardship at Chez Harper leads Alan to become a guinea pig for medical products.
Charlie and Linda attend a function crowning Linda judge of the year but a pill Evelyn gives him believing to be a sedative turns out not to be and he acts crazy at the function, embarrassing Linda in front of the crow
After Alan and Charlie have a fight about Alan's role in the house, Alan packs Jake up and moves in with his mother. Evelyn and Teddy don't want Alan there and go to great lengths to reconcile the siblings.
Charlie writes children's songs and finds success as Charlie Waffles. The kids and their parents love him, even signing CD-s of his jingles. However, Charlie's new found fame irritates Alan.
Charlie & Alan are introduced to Teddy's daughter Courtney. Teddy warns Charlie to stay away from her but Charlie, unaware of what she is capable of, sleeps with her and then gets blackmailed into buying a new Ferrari.
Alan learns Charlie stole away a girl he liked in high school. Seeking revenge he steals Charlie's French girlfriend Gabrielle. However, things don't really work out like he planned due to Gabrielle's behaviour in bed.
Alan is unhappy about his sex-life with his new girlfriend Donna and breaks up with her. Charlie helps a now-free Jake hit on a girl while the two are out dining but it ends up with Charlie getting pepper sprayed.
Charlie sleeps with a woman who is sick & catches her flu. With nobody in his family there to look after him, Rose (back from England) offers her help. Alan feels Jake is pulling away from him which makes him feel sad.
Alan begins dating a divorced woman who used to best-couple friends with him and Judith. He's happy until he learns more about Herb and Judith's sex life than he actually wanted to know.
While at the coffee shop Charlie is recognised by a woman he dated but Charlie can't remember her name. Jake falls for the same woman's daughter so Charlie double-dates with Jake and fixes Alan up with a hooker.
After seeing Charlie with a lot of females in the space of one day, Alan feels Charlie is unable to control his womanising ways. Charlie goes to see his shrink who makes him realise he's missing the one that got away.
Evelyn and Teddy's wedding is under-way and Alan helps the two make plans. Courtney tells Charlie they can't see each other anymore but Charlie can't accept it and takes desperate measures to change her mind.
Evelyn's husband Teddy is found dead in this spoof episode of CSI. The CSIs investigate the death, during which it is revealed Teddy and Courtney are frauds who were trying to steal money from both Charlie and Evelyn.
Alan tries to get Jake to do a book report on The Taming of the Shrew but Jake keeps losing the book. At the library, Charlie seeks relationship advice in the books and becomes attracted to an older self-help author.
Charlie's relationship with Angie is jeopardised when he meets her son's fiancé and realises she is his ex. Things get worse when the ex tries to hook up with him again, ultimately causing his breakup with Angie.
Charlie discovers an ex has a child that looks remarkably like him.
Alan goes too far in effort to collect $38 he loaned to Charlie. Meanwhile, Evelyn arranges a job for Jake.
Alan, Jake and Charlie all decide to try new things. Alan is dating more than one woman, Charlie learns to cook and Jake experiments with beer.
Alan is sure that things will turn bad when Charlie starts dating his receptionist.
Upon discovering Miss Pasternak, Jake's former 5th-grade teacher, turned to stripping after their fling, Charlie tries to help her turn her life around.
When Judith kicks Herb out of the house, Alan hopes to reconcile with her. Meanwhile, Herb tries to adopt Charlie's bachelor ways.
Alan tries to get away from Judith. Meanwhile, Charlie and Herb go out on the town and Charlie uses the threat of military school to get Jake to do chores.
A new girlfriend wants Charlie to sleep over at her place. Meanwhile, Alan has trouble enforcing Judith's grounding of Jake.
Charlie finds himself in an uncomfortable position when Jake takes off with the daughter of a former NFL player. Charlie's Mercedes seems to prove a boon to Alan's love life.
Alan contemplates retiring when Evelyn states that she'll take care of Jake's college education. However, Jake displays a talent that may eliminate the need for college altogether.
Charlie finds himself re-examining his wild ways after an old friend dies during a visit.
Alan finds himself attracted to his receptionist, while Charlie and Jake compete for a waitress.
Alan continues to believe that he is responsible for Judith's pregnancy. Meanwhile, Charlie is convinced he knows the reason behind Jake's bad mood.
When the birthday party she throws for Alan is met with indifference by his family, Melissa feels he's underappreciated and offers him the chance to live with her and her mother.
Charlie agrees to go with Chelsea to couples counselling with Dr. Linda Freeman.
With Chelsea soon to arrive, Charlie must find a way to get a half-naked date out of his bedroom.
Charlie's admission that he's in love with Chelsea gets a surprising reaction from her.
Chelsea's illness gives Charlie a chance to prove he can take care of her whilst also yearning to run away from the situation.
Chelsea's discovery of naked pictures of another woman on Charlie's iPhone leads to his swapping stories of sexual experiences during a drunken night with Alan, Herb and Jerome.
Charlie's desperate to make sure Chelsea and Evelyn don't befriend each other following their first meeting.
Alan lets Chelsea fix him up on a blind date with one of her friends, Rose.
Both Charlie and Alan face lifestyle changes when Chelsea moves into the house.
Charlie seeks to take advantage of Alan and Chelsea's budding friendship. Meanwhile, Alan takes up ventriloquy.
Mia's return finds Charlie questioning how devoted he is to Chelsea. Meanwhile, Alan tries to write a screenplay and the guys rush a labouring Judith to the hospital.
