A mouse is loose in the clinic. Mike goes on a house-call to treat murder mystery writer Olivia Judd. He tells her about an undetectable poison and soon her husband is dead.
Grant's psychiatrist sister Dr. Leona Linowitz (Anne Ramsay) moves into the office upstairs. The single mom is escaping a bad marriage in Chicago. Mike takes her out on a date and it goes badly.
Deirdre is going away for the weekend with wrong number Kevin. He turns out to be a rich guy and he invites the gang to ride his private plane. The problem is that Deirdre's bad luck with men continues.
Leona hires Charles to manage the clinic. None of the partners like him. Leona loathes to fire people and gives Mike the job. Richard falls for the guy and Mike cannot fire him. Also he's rumored to be a psycho.
Mike quits medicine and the TV show. He retreats to a cabin in the Berkshires. His isolation is short-lived. The remaining partners begin the search for a replacement.
Mike's ex Jenna Lathrop has returned. She left the Duke and Mike falls quickly back under her spell. She invites Mike and the gang to her new photo exhibit. She gets Mike to sign the waiver but there is a compromising photo that he missed.
Mike is setting up the old college room for Abe and Gail's anniversary. It even includes a script. Gail is not happy and Abe sleeps on the couch. Mike tries to surreptitiously set up the couple with Leona for a counseling session.
Mike and Richard ask their father for money to fix the roof. Richard suspects that their father is cheating on their mother with Roxanne Abrams (Beth Broderick) after overhearing half a conversation. Faye has dumped her boyfriend.