O Mother, Where Art Thou?: Randall's new girlfriend is the recipient of his late mother's artificial heart. Caitlin dates an older man named Tom while Charlie dates Tom's daughter, and the four of them wind up in family counselling. (S6, E13)

Rags to Riches: Caitlin invites Charlie's estranged con man father (Martin Sheen) to his son's surprise birthday dinner. Paul tries to help Carter mourn the death of Rags. (S6, E14)

Sex, Lies and Video Date: Randall asks Charlie to keep tabs on his niece Stephanie, who makes passes at him. Paul's latest romantic gaffe takes place on a "Blind Date" TV show. (S6, E15)

Eyes Wide Open: Carter joins the Big Brother mentor program, but his visiting Little Brother winds up spending time with Caitlin & an uncomfortable Charlie. The Mayor suffers from insomnia. (S6, E16)

Age Against the Machine: Charlie is exhausted from keeping up with his much-younger girlfriend Tracy. Carter asks Stuart to be his wingman at a gay fundraiser. (S6, E17)

An Affair Not to Remember: Carter pretends to be straight to coach a depressed Paul in the dating game. Charlie and Caitlin have a flashback to their first meeting. (S6, E18)

Let's Give Them Something to Talk About: A therapist helps Caitlin unpack her feelings for her boyfriend Tom & Charlie. Carter helps Paul prepare for an appearance on a phone-in radio show. (S6, E19)

Look Who's Not Talking: Caitlin ends her relationship with Tom & tells Charlie she's interested in dating him. Whilst he's on holiday, Stuart's temporary replacement starts to outshine him. (S6, E20)

A Tale of Four Cities: At a mayors' conference, Caitlin feels awkward because Charlie once had an affair with the organiser, so Caitlin tries to make Charlie jealous. Randall renews his long-standing professional rivalry with Mayor Stone Taylor of Los Angeles (Robert Hays). (S6, E21)

A Friend in Need: Randall tries to please visiting Governor Riley. Charlie and Caitlin struggle to keep their affair secret, and Carter fosters a baby. (S6, E22)