Jake's sullen mood baffles and bothers the family and prompts Alan and Judith to take him to a child psychologist.

When Charlie discovers that Alan is sleepwalking, he believes it's related to his brother's lack of sex following his divorce, and comes up with a cure.

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

Alan suffers from insomnia. He visits his psychiatrist, who reveals that the cause of Alan's sleepless nights is his jealousy towards Charlie, and his inability to glide through life.

Alan and Charlie re-examine their sexual identities after Alan befriends Greg, a gay man. Meanwhile, Jake has a crush on Greg's daughter.

Charlie and Linda get closer to consummating their relationship, but Charlie has trouble focusing when he begins to see Rose's face everywhere he turns.

Alan feels Charlie is unable to control his womanizing ways.

When Charlie meets Angie's soon to be daughter-in-law, he realizes it's not for the first time.

Charlie ends up in couples counseling.

Charlie's admission that he's in love with Chelsea gets a surprising reaction from her

Charlie must make a difficult decision about his future and with which woman he wants to spend his life: Chelsea or Mia.

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

Walden receives divorce papers from Bridget, but forgets his depression when he meets a girl who looks eerily like her.

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