Grazia Mancini (Nadia Cassini) is an aspiring night club singer. Her boss Eva (Karin Schubert) has a lover, John (Elio Zamuto) who is a trafficker of stolen art works. The two learn of valuable paintings hidden in a military mental asylum managed by mentally instable Professor Amedeo Larussa (Lino Banfi). They blackmail Grazia and send her to the mental asylum in the guise of a substitute nurse to learn the whereabouts of the paintings.