Severe sufferers of obsessive-compulsive disorder face their intense, irrational fears in an effort to stop the anxiety disorder's vicious cycle. Under the care of Dr. David Tolin, a clinical psychologist and behavioral expert, the patients move in together to undergo a taxing treatment process called exposure and response prevention. The idea behind it is that OCD can be conquered through repeated and prolonged exposure to feared situations, activities or thoughts. The series chronicles the participants' suffering produced by their never-ending rituals and how, for some, the treatment creates an eye-opening transformation.