Alan wins $500,000 but then finds out Kandi does not love him. A month later Alan is back living with Charlie, who has gone back to the bachelor life. Now, Alan feels he is an all time failure, and no one can cheer him up.

Alan feels guilty when he learns that Charlie and Mia didn't tie the knot because she had wanted him and Jake to move out. Meanwhile, Charlie and his rock star neighbor don't get along.

Charlie attempts to surf in order to impress a beautiful girl -- with disastrous results. He later tells Alan that when his life was hanging in the balance, their deceased father came to him and made a request that Charlie's loath to fulfill.

Alan is determined to gain custody of his and Kandi's dog after she walks away from their split with both the condo and the car. Having also lost everything to Judith following their divorce, Alan decides to hire the best lawyer he knows -- hers.

When Judith announces she's remarrying, Charlie and Alan find themselves helping her fiancA© get over his cold feet so that Alan will finally be free from paying alimony.

Charlie's latest, unusually conservative, classy girlfriend, Lydia, makes her entry in the beach-house in the Harper's hated ma Evelyn's style, almost instantly hurting everybody's feelings, soon in bed and in his favorite restaurant too, but Charlie keeps denying the obvious resemblance till the ugly Oedipal truth becomes too painfully obvious to deny.

Charlie goes with Berta to help her confront the man who impregnated her daughter, who comes to the house to help Berta clean. Meanwhile, Alan has an unusual fetish.

Alan has insomnia but refuses to take pills, opting for a visit to his psychiatrist, who reveals that the cause is Alan's jealously of Charlie and his ability to glide through life.

Alan's failure to ever pick up the check at dinner has Charlie at his wits end, especially after learning of his load of money he has stashed away.

Charlie's latest lover takes over his house and pushes Berta's buttons by treating her like a maid, and he is too influenced by sex to stop her. Meanwhile, Alan's distracted from trying to get Kandi to agree to sell their condo after she asks him for sex.

On Christmas Eve, Charlie's lusty plans for his date are thwarted by guests who keep stopping by, especially Evelyn, who is determined to keep them apart for some unexplained reason.

Charlie discovers that Alan has been secretly dating Berta's daughter and worries about how Berta will take the news, but he and Alan are taken by surprise by her uncharacteristic reaction.

Alan confronts Judith when Jake mentions that he hears his mom and Herb having sex; Charlie discovers that he's repressed his own memory involving his mom and a sexual partner.

Charlie's new neighbor seems uncannily like Alan, which prompts Charlie to try and fix them up with the hope that they'll fall in love---and he'll get rid of Alan.

When Rose announces she is moving to London, Charlie must face his true feelings for her. Meanwhile, Alan tries online dating with unforeseen results. Rose's heartfelt attempt to tell Charlie that she's leaving for good falls on deaf ears. Meanwhile, Alan fudges his profile on an Internet dating service, attracting a fellow profile embellisher.

Charlie is getting older, making love every day or more exhausts him physically, to the point of needing a rest between bangs. So he needs to take his girl Robin -24, about half his age- out again, and brings Alan dancing to a club for her 24-year, ugly girlfriend, a recipe for a miserable night followed by a brotherly row.

When Evelyn expresses sympathy for a friend who had no mourners at her funeral, Alan and Charlie inform her that she's headed for the same fate. Instead of taking their comments as a motive to change, she cunningly makes them regret what they said.

Realizing Jake's childhood is almost over, Alan makes a last minute attempt at father-son bonding.When Jake starts covering his walls with posters of sexy women, Alan feels pressure to make the most of what little childhood his son has left. Meanwhile, Kandi embarks on a new career as an actress.

As Judith's and Herb's wedding nears, Charlie gets close to Herb's witty sister.

Alan prepares Jake for Judith's wedding, while Charlie continues his fling with Herb's sister.

Alan befriends Greg, a gay single dad, causing Alan and Charlie to re-examine their own sexual identities. Meanwhile, Jake has a crush on Greg's daughter, Sophie.

Jake comes into a windfall when Charlie takes him to the track, and Alan is stuck in that special hell known as the Department of Motor Vehicles.

Charlie loses a girl to a young, handsome handyman (Grammy Award winning recording artist Enrique Iglesias), who is working at his house.

Charlie and Alan must confront their daddy issues when Evelyn's new boyfriend invites them to Vegas on his private jet.