After Alan falls off a ladder, Charlie ends up watching over him and Jake, which proves to be a harder task than he thought.

Jake gets suspended from school after he draws a picture of a girl in his class with huge breasts. Charlie is asked to watch over Alan's chiropractic office after pulling an all-nighter, while telling Charlie not to do anything but answer the phone. Charlie turns the place into a get rich quick scheme.

Charlie finds out that Alan has been seeing his ex-wife, which is the reason he hasn't been dating. Alan tells Charlie not to tell Jake because he doesn't want him to get his hopes up. Judith and Alan spend a day together at the house, but Jake keeps interrupting when they try to get sensual in the hot-tub. When they take it to the bedroom, Alan screws everything up for himself.

Berta moves in with Charlie which causes Alan and Jake to move out when she starts butting in to things.

Charlie figures out his commitment issues are because of his unresolved issues with his mother. Jake asks Charlie advice about a girl he likes at school.

Alan dislikes Isabella, Charlie's latest flame. Their rocky start spirals into suspicion of satanic rituals before an unexpeced turn of events scare Isabella off.

Charlie wakes up with Rose the morning after her birthday party. Her father (guest star and father of Charlie Sheen, Martin Sheen) comes to find out what Charlie plans for their future. But what happens when Evelyn shows up is very strange.

Charlie cons Jake into taking ballet lessons in order to get close to the teacher. After his romantic overtures toward an attractive ballet teacher, Mia, are rejected, Charlie will stop at nothing to prove to Alan that he can persuade her to go out on a date with him. When he talks a reluctant Jake into taking her dance class to help his cause, his plan is derailed when Jake falls for her, too.

Alan strikes up a friendship with Charlie's wealthy and amorous neighbor, Norma, only to find himself on the defensive as she puts on a full-court press to win his affections. Meanwhile, Charlie tries to dissuade Jake from donating money to a televangelist.

Charlie helps Alan cope with his lifelong obsession to get women's approval. Alan organizes a family dinner to celebrate the publication of a newspaper article that calls him a good doctor, good neighbor and a good guy, but he's crushed when his mother, Evelyn, isn't impressed. After drowning his sorrow in many drinks, he has a life-changing epiphany and vows to a skeptical Charlie that he is no longer going to grovel for validation from his mother and the other women in his life. * This episode was previously titled Castration and Scallops

Just in time for Christmas, Alan falls for Sandy, the teacher of his cooking class, and before long, she moves into the house, fattens the guys up with gourmet meals, drives Berta crazy with housekeeping tips, and generally turns all of their lives upside down with her unnatural pursuit of perfection. Charlie warns Alan that she's a nester and needs to be stopped before they reach a point of no return. Sandy turns out to be crazy for Santa.

Charlie and Alan drop Jake off at a friend's house and head out for some sibling bonding at the movies, but their night is ruined when Alan freaks out after convincing himself that Jake was too eager to spend the weekend away from him. Recognizing that desperate times call for desperate measures, Charlie begins seeing a therapist, ostensibly to learn how to cope with his brother's ever-increasing emotional instability.

No one believes Charlie when he says that his relationship with Mia is getting serious, and everyone really thinks he's lost it when he confesses that they have been dating for more than a month and haven't consummated the relationship. After a continuing series of chaste dates -- walking on the beach, visiting an art gallery, going bowling -- that end with Charlie frustrated at Mia's doorstep, he makes a proposal that threatens their burgeoning romance.

Charlie plans a romantic date with Mia in the hopes of finally consummating their relationship, but his path to the promised land is blocked when she finds out that he hasn't told his former paramours that he's in a committed relationship. Meanwhile, Alan starts dating Kandi, Charlie's most recent ex-girlfriend, who is half his age.

Charlie can't keep pace with the healthy lifestyle that Mia has introduced to their relationship, so he sneaks cigars and beers in the garage and enlists Rose to deliver burgers to him on the sly. When Mia busts him for lying, Charlie has to figure out if he's just whipped or truly in love.

Alan is having second thoughts about whether he should be dating a woman half his age and is mortified at the idea of introducing Kandi to Evelyn at Jake's birthday party. Meanwhile, Rose continues her passive-aggressive pursuit of Charlie by changing her boyfriend to look almost like an exact copy.

Charlie boycotts an advertising awards banquet, having lost several years in a row to his cocky competitor, Archie. After devising a ploy to get him to attend, Alan, Evelyn and Jake accompany Charlie for support -- until they get to know Archie. Meanwhile, Rose talks Charlie into giving relationship advice to her new beau, Gordon.

When Kandi's old car breaks down, Alan ends up leasing her a new one. Charlie warns him to break things off with her, but when Alan spends his last dime on Kandi's root canal and can't pay Judith's alimony, Charlie is forced to cover for him.

Charlie's not happy when he learns that Kandi has been living in sin with Alan in his house -- particularly since he himself has been having a dry spell with women. Things begin to look up for Charlie when Judith befriends Kandi, and a special visitor comes knocking on his door.

Alan is depressed that his hot young girlfriend, Kandi, has left him to go stay with his bitter ex-wife, Judith, who has brainwashed her against him. At the advice of Mandi, Kandi's mother, Alan goes to Judith's to try to win her back. Meanwhile, Kandi has set Judith up on a date with Andy, her father.

Jake's teacher, Francine, calls in Alan and Judith to discuss Jake's lack of interest in school. Desperate to communicate with someone intelligent while continuing to see his air-headed girlfriend, Kandi, Alan falls for Francine -- in a platonic way. Meanwhile, Charlie helps Jake prepare his audition song for the school musical, which he was forced to try out for by Alan and Judith.

When a cute girl from Jake's school invites him to a party, Charlie butts in on Alan's milestone moment with his son by offering his own words of wisdom on women. While Alan feels somewhat jealous that Charlie is taking over, he realizes that he also feels envious that his son is receiving some solid advice on scoring with women that he wishes his brother had once taught him.

When Charlie finds out that Mia is in town with her dance troupe and has invited him to her performance, he opts not to go and tries to convince Alan (and himself) that he's over her. After surprising Alan (and himself) by showing up, Charlie gets another surprise when Mia explains that she wants something personal from him -- his sperm. Shockingly, commitment-phobic Charlie responds by asking Mia for something as well.

Wedding bells loom as Charlie and Mia make wedding arrangements. But when their families meet, things immediately begin to fall apart. Rose takes the news of the engagement hard, and makes some interesting plans of her own. Additionally, there are questions as to where Alan and Jake will live after Charlie and Mia get married. Ultimately, Charlie and his bride-to-be end up deciding on a small ceremony in Vegas, where a wedding ultimately ensues.