Detective Claudia Studer (Judith Hofmann) is thrilled and full of good intentions when she starts her new job in the homicide squad. But her supervisor (Stefan Huber) there is a grumpy and disillusioned man who seems to have a very low opinion of novices, especially if they are female detectives. The first case takes the disparate pair to the "Sommerfeld" psychiatric institute. The director of the institute was found dead and a patient has disappeared. What seems like a rather unspectacular case at the beginning turns out to be a complicated puzzle. Inquisitive and eager for action, Claudia Studer finds herself confronted with an unfamiliar and menacing world in which the line between sanity and insanity is extremely blurred. With wit, sensitivity and patience she manages to convince her supervisor of her unconventional methods and ultimately solves the crime. Based on Friedrich Glauser's novel «Matto regiert».