Alan has been having a relationship with Lyndsey, the mom of Jake's best friend, Eldridge. When Jake finds out, he stops visiting on weekends and moves in with Judith and Herb permanently, until Alan apologizes to Jake there; Jake gets caught sneaking two girls out of his room; Charlie decides to quit boozing (although all he really does is switch to beer and wine) after a drunken attempt to mail his pants back to the fabric inspector.

Lyndsey tells Alan that she loves him, and asks him to move in with her. At first Alan declines, but after learning that it would upset Judith, he decides to go ahead with the idea, and Charlie bribes Eldridge and Jake with money so that they agree to the circumstances. Later on, Alan encounters Melissa at a wine shop, lies by saying he is single, and then takes her back to Charlie's house to have sex with her.

After having sex with Melissa, Alan finds it hard to let go. He carries on seeing her at Charlie's house and acting as if he still lives there. Eventually, he takes advice from Charlie and Evelyn and ends it with Melissa by text message – causing her to take her anger out on Charlie. Upon his return to Lyndsey's, Alan accidentally sets fire to her curtains, causing a mass fire and leaving them homeless.

After moving into Charlie's house, Lyndsey, Alan, Jake and Eldridge face that they have lost everything with the house fire. Charlie makes fun of them, but forgets his cellphone in the ruin. Going there to get it he meets Lyndsey's ex-husband Chris (Judd Nelson). Later, they are joined by Herb, pizza boy Gordon and Alan. Lyndsey comes to get Alan but ends up going for coffee with Chris. Gordon has to get back to work, Herb has to leave after Judith's call, Charlie returns to his home with a deaf hooker and Alan is left alone in the roof-less ruin.

The episode starts with Alan handing Jake a check for a school trip. Alan becomes depressed after realizing he is broke and lonely. While Charlie heads off to Vegas (although he's really getting cosmetic surgery), Alan pretends to be him. He manages to bring home a woman (Erinn Hayes) he met at the bar, however, she knows that he isn't Charlie. She admits that she and Charlie broke up because he didn't like her role-playing games. Alan ends up going to bed with the woman, but ends up having to dress like Hitler as part of her "game."

Charlie has been dating a woman, Michelle (Liz Vassey), who is four years older than he is, and has trouble adjusting. Matters get even more complicated when he meets Michelle's 20-year-old, bisexual, amateur porn-star daughter and is tempted. Meanwhile, Alan learns that Jake won't visit for the weekend and decides to spend a little "me time", which consists of masturbating in his room, on the sofa, and in the car; but when he does it in a movie theater, he gets arrested, and Charlie neglects to bail him out because he is having sex with Michelle.

When Charlie's new girlfriend Michelle (Liz Vassey) finds out about Rose, she is freaked out about his stalker; she later asks Charlie if he loves Rose and when they both realize he does, she gently but firmly ends their relationship. Rose then tells Charlie she's marrying someone named Manfred Quinn. Charlie doesn't believe her, so he and Alan drive to the church, where the wedding is supposed to take place. As they look through the window, they find Rose getting married and Charlie is left to lament his lost love. However, after they leave, it is revealed that everyone in the church, except for Rose and the priest, are mannequins.

After Charlie ruins Jake's date, Jake vows revenge. When Evelyn's date cancels on her birthday, Jake sees his opportunity to get back at Charlie: he suggests to Alan that they should have a birthday party for Evelyn at Charlie's house. Later that day, Evelyn asks to go to a pharmacist so she can get some birth control pills. She meets Russell, Charlie's pharmacist, and Charlie and Alan decide to set the two up. However, the plan backfires when Russell shows up to dinner with a 30-year-old woman – who ends up having sex with Evelyn.

Berta takes off work for a few days to attend her family reunion and lines up a replacement, Esmeralda. When Esmeralda turns out to be a much better worker than Berta, Charlie and Alan don't want to let Esmeralda go. Meanwhile, Lyndsey decides she doesn't want to get back together with her ex-husband, Chris, and hooks up with Alan again. Then, Alan fears an angry Chris is stalking, threatening, and planning to kill him.

When Courtney (last seen going to prison in "Fish in a Drawer") returns, Charlie gets back together with her. However, she takes advantage of him, making him go on limitless spending sprees for her and injuring him during sex. Eventually, Charlie realizes she is just using him and they break up. But later, after talking with Alan on the deck, Charlie decides to chase after her and get her back, crashing through the glass back door in the process. The episode ends with Courtney visiting Charlie in the hospital, and Charlie shallowly declaring his love for her again.

Alan is destitute as usual, and cannot afford to get Lyndsey a nice birthday gift. He tries raising money by offering massages at the mall, but blows the small amount he earned by buying a "pearl necklace" made out of mints. He considers dipping into Jake's college fund, thinking Jake has no interest in college anyway, but then Jake says he does want to go to college after seeing a porn movie featuring topless female students. Refusing to take the money Charlie offers him, Alan resorts to stealing a pair of earrings from Judith, and has to think quickly to hide Lyndsey's "new earrings" when the two couples show up at the same restaurant. Meanwhile, Courtney takes Jake clothes shopping with Charlie's credit card against Charlie's will.

Charlie and Courtney have grown tired of having sex with each other and decide to break up. Over the next few days, Charlie's behavior becomes increasingly erratic, from writing a depressing song for a new kids' cereal to collapsing in bed with Alan and Lyndsey. After crashing Jake and Eldridge's party at Judith's house, Charlie decides it's time to revisit his psychiatrist, Dr. Freeman (Jane Lynch) to get the help he needs. Later on, he and Alan watch Glee together.

Alan wakes Lyndsey up one night with his sleep-talking. While getting a drink of water, Lyndsey begins talking to Charlie, and the two bond over the love for betting on sports. When Alan learns of this, his paranoia kicks in, and he and Lyndsey have a fight when she wants to invite Charlie to her new house-warming party. Alan spies on the two, but is sprayed by a skunk in the process, and shows up embarrassing Lyndsey in front of her guests. Charlie later tries to tell Lyndsey to give Alan another chance, but this is jeopardized by Alan spying on them again and calling them a bastard (Charlie) and a slut (Lyndsey) because he thinks they are meeting as more than friends.

A few months after her "marriage", Rose bumps into Charlie at the supermarket. Old feelings are rekindled, and Charlie realizes that he loves her. After going to Rose's house and being turned away, the roles are reversed and Charlie stalks Rose, even climbing over the balcony of her deck like she does. Rose continues to reject him, saying that she is now a married woman and must remain faithful to her "husband" Manny. Eventually, Charlie persuades Rose to have an affair with him, and the two end up sleeping together. Meanwhile, Jake and Eldridge film Jackass-style stunts, including swallowing Diet Coke and Mentos to make a "Human Volcano", riding down the roof in a shopping cart, and attempting a fart-propelled launch into the ocean.

Alan discovers that a fellow chiropractor's business is doing extremely well. Seeing as how they started their businesses at the same time and under similar circumstances, Alan determines the reason his business is failing and the other is booming is because of advertising. Alan decides to buy advertising space for all different kinds of media, and asks Charlie for a loan of $5,000 with which to buy the ad space. Charlie hands it over with no questions asked, and Alan, seeing how easy it was, decides to ask his mother for money, too. Evelyn gives $10,000, and Alan realizes that he has come up with a brilliant plan. He offers to let Herb in on a great "business deal," and Herb gives Alan $15,000. Alan pays Charlie back his initial investment of $5,000 plus 20% interest, and Charlie decides to give Alan back all $6,000 plus more, hoping even more interest will be generated by leaving the money in Alan's "advertising fund" longer. Doing the same with Evelyn, Herb, Berta, and even Judith, Alan begins to feel guilty, until he has a conversation with his reflection in the mirror and decides he should take advantage of his good fortune; sort of a reward after years of being stepped on. Meanwhile, Charlie continues his affair with Rose. Gordon, Charlie's pizza delivery man, discovers that Rose's "husband" Manny is really a mannequin, and unsuccessfully tries to tell Charlie.

When Rose wants to invest in Alan's "business", she visits his office and finds out about his scheming and threatens to tell everyone. Alan panics at first, but then he realizes that he can tell Rose's "husband" about her cheating. While over at her house, he finds out that her "husband" Manny Quin is really a mannequin and the penny finally drops on his name. Rose offers Alan the $50,000 he needs to pay everyone back to keep her secret from Charlie, but Alan decides that his loyalty to Charlie is more important; Charlie then insults Alan about moving out after he tells Charlie it's a bad idea to marry Rose, and Alan decides to take the money, pay everyone back, and keep Rose's secret to himself while she and Charlie take a weekend away to Paris. Charlie does "meet" Manny when retrieving something from Rose's closet, but thinks it's just a dummy Manny uses for his fashion designing work. After Charlie grabs Rose's raincoat, the couple head for the airport for their trip to Paris.

Final appearance of: Charlie Harper