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.

Charlie runs into Chelsea's old friend Gail. Alan learns he's able to bring a new female chiropractic patient to orgasm just by working on her lower back.

Charlie and Chelsea's break-up doesn't stop them from sleeping together again.

Crushed over his break-up with Chelsea, Charlie goes missing and comes back to Malibu married.

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.

Alan suspects a widowed lawyer, who represented him following his arrest for slugging a guy at a bar who came on to his date, is interested in Chelsea and suggests Charlie do something about it.

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.

Jake hopes to win back Celeste by writing her love songs. Judith tries to quash Alan and Herb's new friendship.

Charlie helps Jake cheat on his girlfriend while she's away for the holidays. Evelyn brings a television producer to Charlie's Christmas dinner.

Mia's return finds Charlie questionning how devoted he is to Chelsea. Alan tries to write a screenplay. The guys rush a laboring Judith to the hospital.