Samantha Who?:

After Dr. Andy gives Samantha pills as part of a clinical trial to help people with memory loss. At first she is excited that her memory loss misery might finally be coming to an end, but there is a problem. She begins to regain multiple memory fragments - all reminding her of how bad she used to be and what a terrible person the old Sam was. Another problem is that the memories that do return can vanish again as soon as they've appeared, leaving her feeling guilty and apologetic about events, but then can't remember why.

But she discovers one pleasant reminder from the past that could have changed her life forever. Meanwhile, when Andrea and Dena are mistaken for a gay couple, the demoniacally competitive Andrea tries to prove that she could hook up with a much hotter woman than poor old Dena.