Alan is torn between the bad influence of Jake's new friend and the hotness of his mother.

Alan tries for an intimate night at a hotel with his new girlfriend, while Charlie takes a different approach to obtain the "girlfriend experience"

When Jake finds out that Alan has been dating Eldridge's mom, he packs up and heads to Judith and Herb's. Meanwhile, Charlie decides it's time to cut back on boozing.

Charlie is willing to do anything for Alan to accept Lyndsey's offer to move in with her.

After moving in with Lyndsey, Alan continues to have a rendezvous with Melissa at Charlie's house.

Lyndsey and Eldridge move into Charlie's house after their home burns down.

When Berta takes a couple of days off, Charlie falls for her replacement. Meanwhile, Alan believes he's being stalked by Lyndsey's ex-husband.

Alan goes to great lengths to be able to get Lyndsey a nice birthday present.

Depressed after his breakup from Courtney (Jenny McCarthy), Charlie goes to see his psychiatrist (Jane Lynch).

Alan feels paranoid when Lyndsey becomes friendly with Charlie.

Walden goes looking for Mrs. Right while Alan has an opportunity to reconcile with Lyndsey.

Alan has trouble accepting Lyndsey's seedy movie past, and Walden tries to cheer him up by throwing a party.

Upon his release from the hospital, Alan is met with a slew of challenges that test his ability to cope.

Zoey tries to convince Walden to cut his hair and shave; Alan and Lyndsey revive their relationship.

Strained relationships and girl-fighting result when a huge storm traps Walden, Alan, Zoey and Lyndsey in the house on Valentine's Day.

Walden and Zoey's relationship suffers after they share a near-death experience. Meanwhile, Alan wonders if Lyndsey has a drinking problem.

Alan and Lyndsey introduce their mothers. Jake and Eldridge get a ride from Walden to a party.

Walden breaks the news to Zoey that he is going into business with his ex-wife. Alan and Lyndsey try to cope with their mom's relationship.

Walden's commitment is tested when Zoey and her daughter come to live with him. Meanwhile, Alan gets more than he bargained for when he moves in with Lyndsey

Charlie's ghost pays a visit to Alan after he suffers a minor heart attack.

Alan is showered with love and affection upon returning from the hospital, but Zoey isn’t so sure it’s deserved.

Jake is pressured to make a decision about his future.

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

Despite Alan's warnings, Walden starts dating Rose.

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.

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

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.

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

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

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.

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.

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.

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.

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.

Alan and Walden have a meeting with an adoption social worker that hinges on them being convincing as a loving couple. Lyndsey returns after 60 days in rehab.

Walden discovers how challenging it is to be intimate with women when his foster son, Louis, is in the house. Also, Herb asks Alan if he can go on a date with Lyndsey.

When Alan breaks up with their social worker to get back together with Lyndsey, Walden worries it will affect Louis’ adoption.

Walden fears if he breaks up with Ms. McMartin, it will jeopardize his adoption of Louis. Also, Alan hesitates when Lyndsey asks him to move in with her.

After they sign their divorce papers, Walden offers Alan the gift of his choice, but when Alan chooses something selfish and impractical, it puts his relationship with Lyndsey on the line.

Charlie Harper is alive. Or is he?