Charlie and Mia start making their wedding arrangements. Things begin to fall apart when their two families meet each other. They eventually decide on a small ceremony in Las Vegas.

Mia comes back to town with her dance troupe and invites Charlie to her performance. At first, he decides not to go and tries to convince Alan that he no longer has feelings for her. He goes to the see the performance and Mia explains that she wants some of Charlie’s sperm. Charlie responds by asking Mia for something.

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 him advice. Alan and Charlie get nostalgic and remember their first boy-girl party.

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, in a platonic way, because he is tired of the lack of intelligent communication he has with Kandi. Charlie helps Jake audition for his school musical.

Alan tries to win Kandi back. Meanwhile, Charlie starts to sleep with her mom, Mandi, and Judith gets set up with her father, Andy.

Charlie is surprised to find out that Kandi has been living with them for the last three weeks. Alan is having a tough time helping Kandi earn a living. Charlie has lost his sense because of the dry-spell he is going through.

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 is late in paying his alimony check.

Charlie is nominated for an advertising award, but he decides to boycott it because his arch nemesis always wins. The rest of his family tries to trick him into going. Rose is having relationship problems with Gordon and seeks help from Charlie.

Alan has trouble deciding if he should bring his younger girlfriend to Jake's birthday party to meet his mom and his ex-wife. Rose tries to get her boyfriend to act more like Charlie.

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 what he was doing, Charlie has to decide if he is truly in love with her or just whipped.

Charlie arranges a romantic date with Mia in the hopes of consummating their relationship. Alan begins to date Charlie's most recent ex-girlfriend.

Charlie finds himself in a relationship that is not based on sex.

Charlie sees a therapist to learn how to deal with Alan's emotional insecurities.

Alan starts dating a woman with a Martha Stewart complex. Before long she's running the house with an obsession for perfection.

Charlie helps Alan with his obsession of always having to get approval from the women in his life.

One of Charlie's elderly neighbors tries to seduce Alan, while Charlie tries to stop Jake from giving money to a televangelist.

Charlie tricks Jake into taking ballet lessons so he can get close to the gorgeous instructor.

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.

Ignoring Alan's warnings, Charlie continues to date Isabella until she threatens to put a curse on his manhood.

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.

Berta causes tension between Charlie and Alan when she temporarily moves in with them.

Charlie finds out that Alan and Judith have begun to date again.

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.

After falling off the roof, Alan needs someone to watch Jake, and Charlie offers—until it interferes with his social life.