Now that newlywed Alan has moved out, Charlie returns to his bachelor lifestyle.
Charlie finally tells Alan the truth about why he broke up with Mia, and a famous neighbor causes problems.
After nearly drowning, Charlie is convinced he saw his late father.
Alan and Kandi become embroiled in an unconventional custody battle.
Alan and Charlie bond with Judith's new fiancé in an effort to improve his relationship with Jake.
Charlie cannot see that he's dating a younger version of his mother.
Charlie helps Berta confront the man who impregnated her daughter, while Alan indulges an unusual fetish.
Alan seeks a cure for his insomnia, while Charlie pursues the mother of Jake's new girlfriend.
Ladies' man Charlie and tightwad Alan go on a double date, leaving Jake home alone for the first time.
Charlie must choose between his girlfriend and his housekeeper, while Alan looks to sell Kandi's condo but sex keeps getting in the way.
Charlie finds himself throwing an unplanned, unwanted holiday party as Evelyn tries to keep him from bedding his date.
Berta discovers that Alan has been secretly dating her daughter.
When Jake tells Charlie and Alan that he often overhears Judith and Herb having sex, it triggers a repressed memory for Charlie.
Charlie has second thoughts after setting Alan up with their hot new neighbor.
When Rose announces she is moving to London, Charlie must face his true feelings for her. Meanwhile, Alan tries online dating with unforeseen results.
Charlie tries to keep up with a much younger woman.
When Charlie and Alan tell Evelyn they don't think anyone would mourn at her funeral, she replaces them with unlikely surrogates.
Realizing Jake's childhood is almost over, Alan makes a last minute attempt at father-son bonding.
As Judith's and Herb's wedding nears, Charlie gets close to Herb's witty sister.
Alan prepares Jake for Judith's wedding, while Charlie continues his fling with Herb's sister, Myra,.
Alan befriends Greg, a gay single dad, causing Alan and Charlie to re-examine their own sexual identities. Meanwhile, Jake has a crush on Greg's daughter, Sophie. Jane Lynch also guest stars as Charlie's therapist.
Jake comes into a windfall when Charlie takes him to the track, and Alan is stuck in that special hell known as the Department of Motor Vehicles.
Charlie loses a girl to a young, handsome handyman, who is working at his house.
Charlie and Alan must confront their "daddy issues" when Evelyn's new boyfriend invites them to Vegas on his private jet.