Charlie and Kate go to Charlie's sister's baby shower even though he hasn't seen her for ten years, and the group is convinced that Ed's daughter is a lesbian.
Charlie is interested in dating a sexy ex-patient after the five-year mandatory waiting period runs out, but he soon finds out that some of her other former therapists have the same idea.
Charlie comes down hard on his dad after he turns out to be a bad influence on his new friends. Meanwhile, Lacey helps Patrick out with an old high school bully.
Charlie runs into problems after Cee Lo Green hires him as his personal therapist, and things unexpectedly heat up when Lacey hires Nolan to be her photographer.
Lindsay Lohan hires Charlie to be her anger management therapist on the set of a commercial, but Charlie winds up sleeping with her and gets her in trouble after the paparazzi get a hold of it.
Charlie may be forced to move the therapy group out of his house after Lacey gets into a fight with one of his neighbors, while Kate goes with Jennifer to help find a dress for Sam.
Charlie gets Nolan a job with Kate, and uses him to spy on her when Nolan discovers an envelope with dirty pictures in it. Meanwhile, Charlie has a support group created in prison for Lacey.
Charlie deals with Kate breaking up with him and Jennifer getting back together with her ex-boyfriend Sean. Meanwhile, Charlie's group volunteers at a soup kitchen.
Charlie sees a new therapist to deal with new anger issues with Kate, which may open up a new set of issues for Charlie. Meanwhile, the support group plays a trick on Ed for his cruelty.
After his breakup with Kate, Charlie finds a woman who is satisfied with just being "friends with benefits," but is she really being completely honest with herself and with Charlie?
Charlie takes his group on a trip to Lake Tahoe to celebrate a milestone in their therapy, but he returns home early after he receives a text message from Kate.
Charlie has to deal with the aftermath when his father moves in with his patient, and they hit someone with their car. Lacey takes Nolan out to a club.
After Charlie and Kate lose funding for their study, Charlie may have to make a big sacrifice to get new funding. Meanwhile, Nolan's new online girlfriend turns out to be 10 years old.
Charlie hits on Jordan's A.A. sponsor when he discovers that she is a recovering sex addict, and Ed helps Patrick design an outfit for a full-figured woman.
A new patient in Charlie's group claims to be the Devil, and Nolan sells his soul to him to get Lacey to love him. Jennifer and Sam take an interest in their new neighbors, and Martin tries to get Charlie back to church.
Sean is jealous when Charlie keeps sleeping with Jen after he tells Charlie that he wants her back, so he looks to get revenge. Meanwhile, the therapy group helps to make Patrick unattractive so that he can find a new man.
Charlie asks for a second chance with the woman to whom he lost his virginity, and Lacey and Patrick try to keep up appearances when Lacey's parents pay a surprise visit.
A problem arises when Charlie sleeps with a reporter who is writing an article about the sex study, while Lacey tries to take advantage of Nolan's lingerie store employee discount.
