Despite warnings from Charlie, Jake continues to feed seagulls on the deck and the birds invade the house. Meanwhile, Charlie thinks Judith is taking advantage of Alan, who keeps going to her house to fix things.

Alan and Charlie have encounters with some highly libidinous soccer moms, but with two very different outcomes.

Alan tricks Charlie into joining him and Judith in leading Jake and his classmates in the school's annual music show.

Charlie's financial manager informs the carefree jingle writer that he spends money faster than his royalty checks come in, and now he must go on a budget.

Charlie's still brooding over Alan's choice of their cousin as Jake's guardian if both parents die when the boy has an accident while in his care and has to be rushed to the hospital.

Judith's devious siren sister stirs things up at Jake's 11th birthday party when she hits on Alan. Meanwhile, Evelyn brings alcohol and has a party of her own.

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.

Judith is dating Jake's pediatrician, and Alan is upset until Charlie points out that if she remarries, his alimony payments will end.

Jake is very impressed and can't stop talking about his mother's new boyfriend, Dr. Melnick, which annoys Alan. While Evelyn borrows Charlie's car to help her impress a Saudi prince, because she wants to sell him real estate. When Charlie gets his car back, he discovers his mother's bra in the backseat. When he finds out why it's there he decides to trade in his car.

Alan denies having shoplifted a toy as a child and fears he has a dark side, until Charlie admits he planted the toy on Alan to stay out of trouble himself.

Alan is jealous of Charlie when an old classmate, who's now a beautiful woman, seems to be more interested in Charlie.

Charlie is invited to a party hosted by a gay ad-executive named Eric, so Charlie asks Alan to pretend that he's his life partner. While at the party, Charlie meets Eric's ex-wife Pamela, and tries to sleep with her without Eric finding out.

Evelyn reads in the obituaries that her second husband, Harry has died. They all attend the funeral, including Jake who is excited at the opportunity of seeing a ""dead guy"". Charlie is excited by the opportunity of a newly single widow, and Alan is just happy to pay his respects to Harry.

Jake gets suspended from school after drawing an offensive picture of a girl in his class that has large breasts. Meanwhile, Charlie is asked to watch over Alan's chiropractic office after pulling an all-nighter.

Charlie finds himself in a relationship that is not based on sex.

Charlie is nominated for an advertising award, but he decides to boycott it because his arch nemesis always wins. The rest of his family tries to trick him into going. Rose is having relationship problems with Gordon and seeks help from Charlie.

Charlie is surprised to find out that Kandi has been living with them for the last three weeks. Alan is having a tough time helping Kandi earn a living. Charlie has lost his sense because of the dry-spell he is going through.

Jake’s teacher has a meeting with Alan and Judith to discuss the lack of interest Jake has at school. Alan starts to fall for Francine, in a platonic way, because he is tired of the lack of intelligent communication he has with Kandi. Charlie helps Jake audition for his school musical.

Charlie finally tells Alan that he didn't marry Mia because she wanted Alan and Jake to move out of the house, but Alan finds a hole in his logic. Charlie and Alan deal with a noisy neighbor who constantly sings all the time, who happens to be Steven Tyler.

Charlie tries to surf to impress Dottie, a beautiful woman he just met, but after he nearly drowns he is convinced that he saw his late father.

Berta's daughter, Naomi is pregnant and Berta drags Charlie with her when she confronts the baby’s father. Alan reveals a secret fetish.

Worrying Charlie may get rid of one of them, Berta and Lydia fight over him. Meanwhile, Kandi does everything she can to stop Alan from selling their condo.

Berta discovers that Alan has been dating her daughter Naomi.

Rose is moving to London, and Charlie is surprised by his reaction to the news. Alan lies to a woman he met online.

Charlie's young, hot girlfriend takes him to a new club. She invites Alan to meet one of her friends but the men are shocked to learn that they are considered as being "old".

Charlie takes a liking to Myra, the witty sister of Judith's fiancé, Herb.

Alan looks forward to Judith's wedding, while Charlie and Myra continue their romance.

Evelyn's boyfriend, Teddy, invites Alan and Charlie to go with him to Las Vegas on his private jet. The boys confront their individual 'daddy issues'

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.

Charlie has to come up with ways to keep his girlfriend's 4-year-old amused; Alan becomes a test subject.

Charlie fights his attraction for Teddy's daughter.

Charlie double-dates with Jake and fixes Alan up with a hooker.

Alan makes wedding plans for Evelyn and Teddy, while Charlie figures out how to get more acquainted with his future step-sister.

Charlie's attracted to an older self-help author. Alan and Jake clash over a project for school.

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

Charlie borrowed money from Alan and on the day he is supposed to pay him back, Alan goes to ask Charlie for the money. He again finds Charlie in bed with a beautiful woman. After Charlie shoos him out and assures him he'll get the money for him later that day, the woman asks if Charlie is really out of cash and Charlie tells her not to worry, that he has plenty of hooker money.

Alan is sure that things will turn bad when Charlie starts dating his receptionist.

Charlie tries to help Jake's former teacher, who became a stripper after dating him, but things go from bad to worse when she has a religious conversion.

Alan tries to escape Judith's grasp as Charlie and Herb go on the prowl to pick up women. They later end up going back to Herb's hotel room with two prostitutes, where Herb declares his love for Judith and races over to win her back.

Charlie finds himself in an uncomfortable position when Jake takes off with the daughter of a former NFL player. Charlie's Mercedes proves a boon to Alan's love life.

Charlie finds himself re-examining his wild ways when an old friend dies and begins to feel that his time on Earth may be drawing to a close.

Charlie and Jake fight for the affections of a waitress, while Alan fights sexual tension with his receptionist.

Charlie has to remove a half-naked woman from his bedroom before Chelsea arrives.

Chelsea's illness gives Charlie a chance to prove he can take care of her, but also yearning to run away from the situation.

After Chelsea discovers a nude picture of another woman on Charlie's cell phone, he blows off steam by going out for a night of drinking with Alan, Herb and his neighbor.

Charlie's desperate to make sure Chelsea and Evelyn don't befriend each other following their first meeting.

Chelsea is asked by Alan to arrange a blind date between he and her new friend, unaware that her new friend is Rose.

Charlie mourns the loss of his bachelor pad as he reluctantly allows Chelsea to move in. Meanwhile, Alan discovers there is no longer much space left in the house for him.

Alan and Chelsea become best buds, and Charlie decides to take advantage of the situation.

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

Alan starts working for Evelyn as Charlie works to fix the relationship between Chelsea and Jake.

Jake is taught the art of infidelity by Charlie, while Celeste is away for Christmas.

Charlie has a return engagement with Chelsea's best friend, while Alan has an unexpected effect on a new female patient.

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

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

Charlie and Alan try to set up Evelyn with Russell the pharmacist.

Obsessed and believing her to be married, Charlie starts stalking Rose. Jake and Eldridge start taping themselves doing Jackass-style stunts.

While Charlie and Rose carry on their "affair," Alan's chiropractic business turns into a Ponzi scheme.

Alan and Jake meet Walden Schmidt, a broken-hearted billionaire.

Walden deals with his ex-wife, Bridget.

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.

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

Jake has a crush on his chemistry tutor, who has a crush on Walden. Meanwhile, Alan obsesses over the journal his brother left him in his will.

When Walden begins redecorating the beach house, Alan becomes overly emotional.

Walden hits it off with a British babe, but neither of them is sure he's ready to re-enter the dating world.

Walden is trying his best to impress his new love interest when Bridget reappears in his life.

Walden's mother arrives and Alan is smitten with her, even as she reveals a secret about Walden's past that sends him into a downward spiral.

Walden’s ex-wife and mother try to take control of his company, so he turns to Alan for help.

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

Walden tries to loosen Zooey up by sharing some of Berta's special brownies.

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.

Walden's ex-business partner shows up at the beach house looking to make peace.

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.

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.