Alan is sure that things will turn bad when Charlie starts dating his receptionist.
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.
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.