Jenny moves in with Evelyn and her boyfriend when Walden begins to feel cramped in his own house; Alan becomes the "other man" in Lyndsey's relationship.
Jack spots Chrissy with his money in her possession, and evidence begins to mount towards the conclusion that Chrissy has a strong compulsion to steal.
Jack becomes excited when Chrissy lands him a job catering an executive party at her office, but problems arise when he attempts to defend Chrissy's honor.
Mr. Roper discovers that he can hear into the trio's apartment through pipes in his home, and a misunderstanding leads him to believe that Chrissy is pregnant.
Janet's date at the apartment is ruined by Jack and Chrissy; Mr. Roper fears legal action from Jack after he accidentally breaks his leg on the property.
Jack is offered a chance to become a live-in cook for Larry's boss, and he decides to take the job after a particularly heated argument with his roommates.
Mr. Roper tells the roommates that he has a surprise for Mrs. Roper for their anniversary, but the trio believes that their landlord is implying a divorce.
Evelyn and Chelsea begin spending time together, making Charlie desperate to find a way to keep them apart; Evelyn out-wits Charlie by paying-off Alan and Jake.
Alan goes on a blind date with one of Chelsea's friends, but is shocked to find that the friend is Rose; Charlie is stunned when the two of them hit it off
Charlie reluctantly allows Chelsea to move in, as he mourns the loss of the bachelor pad; Alan and Jake must become acclimated to a woman in the house.
Charlie questions his relationship with Chelsea when he hears that Mia is back; Judith goes into labor and Charlie, Alan, and Herb rush her to the hospital.
Alan is forced into taking care of Judith's baby when his ex-mother-in-law becomes tipsy; Jake blackmails Charlie after he accidentally runs over Chelsea's cat.
Alan takes a job working for Evelyn so that he can eventually move out of Charlie's place; Charlie attempts to close the rift between Chelsea and Jake.
Alan suggests that Chelsea should get breast reduction surgery, and Charlie responds by kicking him out of the house; Evelyn allows Alan to move in with her.
After Charlie and Chelsea set their wedding date, he and Alan go out, only to awaken perplexed as the two of them are in the same bed with a strange woman.
Chelsea invites her gorgeous college roommate to stay at Charlie's after she undergoes a rough breakup, resulting in Charlie secretly hoping for a threesome.
When Jake's girlfriend goes out of town for the holidays, Charlie encourages him to hook up with an attractive girl he met at the beach, but Alan disagrees.
Jake attempts to woo his ex-girlfriend by writing her a love song; Alan and Herb try to keep their friendship hidden from Judith, knowing she wouldn't approve.
Alan ends up in jail after being involved in a bar fight, and Charlie becomes worried that Chelsea might be interested in the lawyer who takes the case.
Attempting to win over newly engaged Lisa, Charlie bribes his family to come together for a customary Thanksgiving dinner to portray himself as a "family man."
Charlie's jealousy of Brad begins to agitate Chelsea to the point of threatening their relationship, so Charlie approaches Alan for advice on what to do.
After becoming depressed when Chelsea dumps him, Charlie runs off to Las Vegas and returns home with a new wife, but he soon finds she comes with complications.
Charlie hooks up with one of Chelsea's best friends; Alan unexpectedly discovers that he is capable of having an intriguing effect on his female patients.
Alan finds himself attracted to the mother of Jake's friend, but is unsure about the relationship when he sees the negative influence the boy has on Jake.
To create an intimate evening, Alan books a hotel for him and Lyndsey, but a problem arises; Charlie hires a prostitute to act like a girlfriend would.
Jake moves in with Judith and Herb when he discovers that Alan is sleeping with Eldridge's mom; Charlie contemplates sobriety after an interesting night.
Lyndsey asks Alan to move in with her, but he is reluctant; Charlie pulls out all the stops in an effort to encourage Alan to agree to Lyndsey's request.
Alan makes friends with Lyndsey's boyfriend in an effort to find out what he has that Alan doesn't; Walden helps Jenny be more proactive with her acting career.
When one of his close friends is betrayed in a business deal by a Vegas kingpin, Danny Ocean gathers the group and puts a plan together to exact revenge.