Walden plans a big surprise for Zoey's birthday.

Zoey and Walden break up, causing Walden to experience a breakdown.

Alan and Lyndsey decide to spice things up in the bedroom.

Walden starts to feel his age when a friend's daughter comes to town.

Despite Alan's warnings, Walden starts dating Rose.

Walden must choose between Zoey and Rose.

When Walden gets tired of the complications that come with a traditional relationship, he hires an actress to be his girlfriend; Jake plans a rendezvous with Missi (Miley Cyrus) at the beach house.

Alan feels reluctant to make a commitment to Lyndsey, but an unexpected source inspires him; Walden enjoys being the boy-toy of a wealthy older woman.

Alans famous ex-wife, Kandi, wants to reconcile; when Berta isn't interested in celebrating her birthday, Walden tries to make her day special.

Alan helps Walden create a new identity so he can avoid women who are only interested in his money.

Walden juggles his two identities; Alan ends up alone on Christmas.

Alan invests Walden's money in Kate's fashion line; leading a double life takes its toll on Walden.

Alan and Walden go to Kate's fashion show in New York so Walden can reveal the truth about his identity.

Alan is faced with relationship trouble when he does not give Lyndsey a key to the beach house; Walden, Alan, Herb and Billy commiserate about relationships.

When Jake brings his 36-year-old girlfriend home for a visit, Alan is concerned; Walden tries to hide something from Alan.

Depressed on Valentine's Day, Walden tries to talk Kate into giving him another chance; Alan's holiday plans go south.

When Walden runs into his ex and they start talking about getting back together, Alan worries that she is not good enough.

After a fight with Walden, Alan decides to move in with Herb.

Alan and Walden end up partying too hard as they try to cheer up Herb.

Walden and Alan are caught in the crossfire when Jake cheats on his girlfriend (Jaime Pressly) with her 18-year-old daughter.

Alan has a difficult time coping when Lyndsey breaks up with him.

With encouragement from Walden, Alan decides to update his look; Alan is faced with a moral dilemma when he attracts a married woman.

Walden dates an attractive 22-year-old (Hilary Duff), but ends up being more interested in her grandmother (Marilu Henner); Jake and Alan go on a trip.

Charlie's 25-year-old daughter arrives at the beach house, hoping to get to know her family.

Jenny moves in with Evelyn and her wealthy boyfriend, Marty (Carl Reiner).

Walden and Alan think it may be time for Berta to retire when she injures her back at work. When they suggest her retiring, she grows offended, and as the conversation progresses she quits. Walden and Alan then try different maids, with little success.

Alan and Lyndsey's illicit relationship becomes jeopardized when one of Lyndsey's man-hunting friends, Stephanie (Jennifer Aspen), asks if they are back together. The two staunchly deny it, then Lyndsey insists that Alan make a date with Stephanie so that she will believe their lie. Alan meets her for an uncomfortable date, which nevertheless leads to sex, causing Lyndsey to get mad and leave Alan again.

Alan tries to find out what Lyndsey's boyfriend has over him; Walden helps Jenny pursue her acting career.

When Alan learns Walden knows Lynda Carter, he asks him to set him up on a date with her. Against his better judgment, Walden agrees to invite her to the house for dinner.

Walden and Alan find themselves on dates with two ideal women until Lyndsey's jealousy throws a wrench in their evening.

Alan and Lyndsey’s illicit affair puts Walden in danger, forcing him to accept Rose’s help.

Walden goes on a date with an accident-prone model; Alan's date reveals surprising personal information about herself to him.

Jake sends Alan a Japanese delicacy; the house comes alive with questionable Christmas lyrics.

Walden joins his beautiful former employee on a brilliant new project. Meanwhile, Alan advises Jenny to open up to her girlfriend or risk losing her.

Lyndsey's boyfriend sets Alan up on a date; Walden wants to help Nicole with her project so she will have time to date him.

Marty Pepper (Carl Reiner) proposes to Evelyn; Alan and Walden plan a bachelor party for Marty.

Alan finds out that Lyndsey broke up with Larry without telling him; Walden tries to prove he is a man's man.

Alan asks Lyndsey to choose between him and Larry; Jenny worries that she and Brooke are growing apart.

Walden thinks his girlfriend is cheating on him; Alan starts dating Larry's sister, Gretchen (Kimberly Williams-Paisley).

Lyndsey finds out about Alan's relationship with Gretchen; Walden has a difficult time telling Barry to find his own place.

Walden gets an invitation to his ex-girlfriend's boutique opening. Meanwhile, Gretchen wants to spend more time at Alan's (a.k.a. Jeff Strongman) house.

After reconnecting with Kate, Walden becomes convinced she is the one for him -- until he meets a woman named Vivian (Mila Kunis).

Alan finds an opportunity to make money; Walden addresses his co-dependency issues.

Alan's girlfriend, Gretchen, insists he confess his true identity to Larry. Meanwhile, Walden goes on a road trip with Jenny and Barry to see his first car.

Alan must face the consequences after revealing his identity to Larry.