ABC
Despite Cooper catching Charlotte and Sheldon mid-sex last episode, Coop enlists Sheldon's "expert" opinion on his eleven-year-old patient with an imaginary friend. Turns out she's actually schizophrenic, and her parents are in varying levels of denial and then acceptance.
Ultimately, they choose treatment, but not until Cooper and Sheldon have messed up each other's faces in the Oceanside breakroom (don't ask me why Sheldon was there at all) in the most juvenile and silly fight of all time. Charlotte, meanwhile, is just there to break up their fight, to slam the door in Sheldon's face, and then to make out with him in the end. Oh, and they have absolutely no chemistry. Zero.