After 12 years of marriage, his wife Judith, kicks Alan out. He turns to his older brother Charlie for help. Charlie has trouble adjusting his carefree lifestyle with the presence of his 10 year old nephew.
Alan punishes Jake for an incident at Judith's house. Charlie is lax in enforcing Alan's restrictions, then some seagulls invade Charlie's house as a result of Jake's actions, Charlie has to learn how to discipline his nephew.
As Charlie tries to write a new jingle, Berta quits. Alan tries to convince her to come back. Leaving Charlie to get Jake ready for a dinner. And Rose tries to get Charlie's help to prepare for a date.
Jake sees a butterfly tattoo on the firm bottom of a surfer-chick friend of Charlie's, which is the start a string of harmless events that become larger and more disastrous with each action. This is not unlike the famous chaos theory's Butterfly Effect, asking if the flap of a butterfly's wing in Brazil, could set off a tornado in Texas.
After being tricked into helping Alan and Judith produce Jake's classroom musical, Charlie is flattered to find out that the kids know all the words to his jingles. Alan is blind-sided with divorce papers from Judith, causing strife which results in Charlie, who refuses to deal with the pre-pubers without a snootful, having to produce the play on his own. Jake is crushed when he realizes that a reconciliation between his parents may never happen.
Thanksgiving winds up being the least thankful day of the year for Charlie, who has to bribe various members of his household to even come to a traditional turkey dinner. Not only are the usual feuds in evidence (leading to a turkey-carving right out of "Psycho") but Judith's parents are actually sympathetic to Alan and hostile to their own daughter for her "fling" with lesbianism.
Now Frankie has tricked the Harpers into taking her and her daughter Joanie in, she explains that Bob's parents want her declared mentally incompetent in order to get custody. Charlie wants to dump her, but Alan insists on taking them both in. Jake doesn't enjoy the 8 year old's 'romantic' attention. Charlie hates the consolation kisses and compliments, and is stunned when Frankie prefers intimacy with Alan. Charlie rightly warns him he's just falling for his 'damsel in distress', but warns her not to hurt his kid brother.
Jake verbringt das Wochenende bei seinem Vater Alan. Doch was ein harmonischer Tag werden sollte, wird zum Desaster, denn Jakes ständige schlechte Laune geht Alan und Charlie mächtig auf die Nerven. Die beiden versuchen den Grund für Jakes seltsames Benehmen herauszufinden, bleiben aber erfolglos. Die letzte Hoffnung ist der Termin bei einer Kinderpsychologin. Als alle Bemühungen scheitern, hat Haushälterin Berta eine verblüffende Idee.
After Charlie is given a witness interview by Alan's expensive, power-hungry divorce lawyer, Laura, she sets her sights on him, but warns him that it must be kept a secret, giving him strict ground rules to follow. Unaware of what is going on, Alan is feeling somewhat confident about the possibility of a fair custody/settlement agreement, despite Judith's concerns about Jake living at Uncle Charlie's house on weekends. When Charlie brings home Laura's paralegal to play, and Laura catches them together, Charlie finds her reaction to the situation unacceptable. Alan in dumbfounded when his lawyer tanks his case.
Alan has consented to pay for Jake's appointment at the child psychologist, self-confessed mere guesser Dr. Freeman. Charlie finds that Alan is the one who sleepwalks and performing domestic chores, and hears from ma Evelyn it had happened before - from their dad's death till Alan's sexual awaking. Arranging a sex-life for Alan fails as he refuses one night-stands, so Charlie finally drags Alan to the child psychologist, and ends up as a stand in for Judith.
Jake repeats something Charlie says to Judith. Then Judith refuses to let Alan take Jake for the weekend. Alan tries to talk to Judith, but encounters resistance from Judith and her friends. It's up to Charlie to set things right.
Charlie is sure he isn't ready for fatherhood after a year of trying to raise Jake, so he opts to have a vasectomy. But when the doctor performing the procedure keeps getting calls from his wife -- who's about to give birth -- Charlie starts to think about what fatherhood might entail and likes the idea, provided he still has his vital organs intact (in more ways than one).
Charlie is having some friends coming over to his house to have a gathering but Alan is not invited. Things got worse when Alan is also not invited to Judith's party even though her guests are Alan's friends.
After Jake flips off his teacher, Alan and Judith move to punish him. Charlie, meanwhile, has other plans for Jake's teacher. Chaos ensues when Jake discovers the relationship and the increasingly overbearing Miss Pasternak tells Charlie she believes God brought them together.
After Charlie reluctantly lends Evelyn his new car, he later discovers her bra in the back seat. Meanwhile, Alan is forced to compensate after Jake gets attached to Judith's rich and talented boyfriend.
Charlie is dating a self-assured woman who plays hard to get, easily dismisses him, and he finds it disarming. Rose gets Charlie to see that his new lady-friend, Sherry, is in his head because she is just like him; a self-centered, manipulative, narcissist. Charlie debates breaking it off. Alan and Jake fiercely battle wills over Jake doing his homework.
Evelyn announces she is receiving an honor from the real estate industry and that Charlie and Alan will host a party in her honor. Mayhem ensues when Berta and her sister agree to cater the event, but sibling rivalry takes center stage.
After finding out that Jake has spent the night at his other grandparents's house, Evelyn insists that Jake spend a night at her place. After convincing Jake to stay at her place, Alan and Charlie worry about how Jake will be affected by his overnight visit.
Charlie gets drunk and sleeps with Rose on her birthday. Rose says she knows it's no big deal. But her father quickly shows up at Charlie's house, under the impression that they've been dating for two years.
Charlie has to decide whether he can really commit to a serious relationship with Mia, especially when sex is currently off the agenda. Unsurprisingly, his suggestion that he sleep with other women in the meantime falls on somewhat stony ground.
Forced to hide in his garage to enjoy a brace of beers and half a Cuban cigar, Charlie's attempts to keep his unhealthy lifestyle habits secret from Mia fall apart when she smells bacon on his breath, resulting in their first major argument since taking their relationship to a physical plane.
As Jake's twelfth birthday approaches, Alan is still smiling ear-to-ear over his sex life with 22 year-old hottie Kandi, even when he's forced to explain to his son what a "booty call" is. Meanwhile, Jake celebrates with a sip of coffee and a handful of vitamins - or at least, that's what he assumes the blue pills in his dad's bathroom cabinet are, with the "V" imprinted. Like Berta says, he's going to need another party hat.
At Alan's insistence and to avoid having to escort the daughter of one of ma's clients (she invited that), Charlie attends with Alan, ma and Jake the jingle awards ceremony, where he's nominated and just knows Archie Baldwin will win for the seventh year in a row, because that pompous ass always gets the sexy products, a good tune for medication like Charlie's clients is never good enough to get a fair chance. He's right, and was forced by Rose -who will otherwise stalk him again- to make her adoring teenage boyfriend Gordon give her some private space again; when that works, she changes her mind...
Alan finally has an attractive date, 22 year-old Kandi, but she's even dumber then Jake, and as Charlie rightly points out girls that age are extremely high maintenance. Charlie has his fun seeing Alan struggle with the growing pile of bills, driving him to raid Jake's mammoth piggy bank and taking a second job as pizza deliverer, but still helps his double-plucked brother when wicked ex Judith insists on alimony. Alas Kandi...
The Harpers's world is inverted: Charlie's ex Kandi, of his countless girls about the dumbest, not only became Alan's lover but even says she prefers sex with him, and has been living in Charlie's beach-house, as unnoticed as several furniture changes, for three weeks since she was evicted. Charlie has suffered a sexual drought even longer, by now even Berta and her cousin in prison begin to look somehow attractive. Judith finds out, and is shocked Jake is exposed to such a floozy; despite his brother's warning to keep love and business apart, Alan tries her as secretary in his surgery, with even more and worse results then either could fear...
Alan is made to admit to Charlie, who keeps hitting it in, he has hit rock-bottom now his brainless girlfriend Kandi has moved in with his ex. It's all so confusing that Jake would prefer dad's ladies to be lesbians, then tells him Kandi's ma Mandi has joined Charlie's endless list of sexual conquests. Alan can't talk to Kandi, she just repeats Judith's phrases, clearly without understanding the words, but he sees her dad, Mandi's ex Andy, arrive on blind date with his own ex Judith. Frolicking finale at Judith's, in rooms, bed and hot-tub...
Jake has his first boys-girls party, dating a smart girl, Wendy Cho. Alan was looking forward to coaching his son, but even Jake, who spends his schooldays watching the clock tick, isn't dumb enough to consider dating advice from the worst womanizer in L.A., while Charlie proves he can coach a virtually hopeless case -Alan and Judith's genes without the IQ- trough appearance, dance and anything else. In fact Alan envies Jake so much, he still hopes for ...
When Judith announces she is going to remarry, Charlie and Alan must convince her fiancé to proceed with the nuptials after he displays signs of cold feet, so that Alan can discontinue alimony payments to Judith.
After a bout with insomnia, Alan is escorted home from a midnight run on the beach by the local sheriff's department. Jake fights back when Charlie goes back on his word about not dating his friend's mother.
Charlie tries to set up Alan with the sexy and rich new next-door neighbor who is looking to settle down. But when Charlie discovers her secret history as a drunken slut, he decides to go after her himself.
Charlie discovers that being a children's singer means making lots of money and picking up single moms. But he also discovers that he's going to have to overcome his fear of performing in front of large audiences.
Charlie is acting even more promiscuous than normal, which is getting him in trouble with a lot of husbands and boyfriends. With the help of his psychiatrist, he discovers it's related to his ex-fiancée's upcoming wedding.
Charlie dates a self-help author who is much older than him, has a 32-year-old son, and treats him more like his son than his boyfriend. Jake tries to write a book report over the weekend, but keeps losing the book before he can read it.
Alan is overjoyed when he learns that Judith and Herb's marriage is on the rocks, but he gets more than he bargained for when he tries to fake-comfort her. Meanwhile, Herb tries picking up women with Charlie's help.
Alan and Judith start seeing each other again after Judith's breakup with Herb, Herb continues to turn to Charlie for help picking up women, and Charlie messes with Jake by threatening to get him sent to military school.
Chelsea is jealous when Charlie's ex fiancé, Mia, calls him--perhaps rightfully so. Meanwhile, Judith goes into labor, Herb is incapacitated, and Alan runs into his ex-girlfriend and receptionist at the hospital.
Chelsea encourages Charlie to help his ex-fiancé Mia launch her music career, but does he still have feelings for her? And what if she's a terrible singer? Meanwhile, Alan wants Charlie to let Melissa move in with him.
Charlie hooks up with Chelsea's best friends, which could cause problems when Chelsea wants to get back together. Meanwhile, Alan is paid handsomely by a chiropractic patient who wants a different kind of adjustment.
Alan unsuccessfully tries to keep Jake from finding out that he's sleeping with his friend Eldridge's mom, while Charlie contemplates giving up drinking after an unusually wild night he can't remember.
Jake gets Alan to invite Evelyn to Charlie's house for her birthday dinner to get revenge for Charlie ruining his chances with a classmate, and Alan and Charlie get Charlie's pharmacist to come along as Evelyn's date.
Alan's efforts to ask family for money to help promote his struggling chiropractic business turns into a Ponzi scheme, and Charlie continues to see Rose, still completely unaware that her "husband" is actually a mannequin.
Charlie hat in Paris den Tod gefunden - woran Rose nicht ganz unschuldig ist. Nun findet in seiner Villa in Malibu die Beerdigung statt. Neben seiner Familie sind auch alle seine Ex-Frauen da, was Alan jede Menge arbeitet bereitet. Zumal aus dem Meer später auch noch Walden Schmidt auftaucht. Der Internetmilliardär wollte sich im Meer am Strand von Malibu das Leben nehmen. Allerdings war ihm das Wasser dann zu kalt. Nun landet er geradewegs im zum Verkauf stehenden Haus von Charlie, in welchem noch Alan und Jake wohnen. Allerdings könnten sie sich das Haus alleine nicht leisten.
Walden buys Charlie's house and hires Berta as his live-in housekeeper, forcing Alan to move back in with his mom. However, Alan sees an opportunity to come back when Walden asks for advice about getting his wife back.
Walden hires Evelyn as his interior decorator, but Alan is convinced that she just wants to take advantage of him sexually. Meanwhile, Alan inherits Charlie's journal, and Jake has a crush on his tutor, but she has a crush on Walden.
While Walden takes a job as a Christmas tree salesman as part of his ruse, he gets a billion dollar business proposal from Mark Zuckerberg. Meanwhile, Alan finds himself completely alone at the beach house for the holidays.