After a party in a clinic, a patient found consciousless and the director is missing. A film noir entering in the world of psychiatry. If any one man is responsible for the rejuvenation of the postwar Swiss film industry, that man was director Leopard Lindtberg. Matto Regiert (Madness Rules) was co-adapted for the screen by Lindtberg from a novel by Friedrich Glauser. Heinrich Gretler stars as Sergeant Detective Studer, the hero of several of Glauser's most popular works. This time, Studer must solve the murder of the director of an insane asylum -- and it's not (surprise, surprise) the most likely suspect, manic-depressive patient Olaf Kubler. For box-office purposes, Matto Regiert stresses a romantic subplot involving Kubler and nurse Elizabeth Muller.