When Charlie's jealousy threatens his relationship with Chelsea, he turns to Alan for help in becoming a better person. But will he be able to pull it off?
Charlie hooks up with Chelsea's best friend, 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 dates the mom of one of Jake's friends instead of telling her that her son and Jake went out drinking, but Charlie surprisingly does not approve of his actions.
Alan's plan for a romantic overnight getaway with his girlfriend hits an unexpected snag, while Charlie has an unusual request for his overnight companion.
While Alan and Jake go to Sacramento to pick up a grandfather clock, Charlie gets a prescription for medical marijuana to help him sleep and forget about Chelsea.
Alan unsuccessfully tries to keep Jake from finding out that he's sleeping with his friend Eldridge's mom; Charlie contemplates giving up drinking after an unusually wild night he can't remember.
Charlie has second thoughts about the woman he's dating when he discovers she's 47, but his attitude suddenly changes when he discovers she has a sexy, bisexual, 20-year-old daughter.
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.
While Berta is away for the weekend, Charlie finds the perfect replacement housekeeper; when Lyndsey starts dating Alan again, her ex starts stalking him.