Sitting at a table in an empty room, a man listens to an interrogation tape. It relates to how the man was found in Turin, doesn’t know his name and was locked away in a psychiatric institution. Characters from his possible past are used to find out who he is. He is taciturn, mumbles an answer now and then, and gives the impression that he actually knows some of the details, but quickly forgets others. We are shown photos of places where he may have been and follow him being given a number of simple language and maths tests which the detective employs to solve this mystery.