Detective Hans Barlach is aging. He has been sick with cancer but is slowly recovering after surgery.

One day, he notices that his friend Samuel, who works at the hospital as a doctor, suddenly turns pale when he sees a picture in LIFE magazine.

The man in the picture is said to be the German doctor Nehle, who, in horrific ways, performed surgery on prisoners without anesthesia in the Stutthof concentration camp, and subsequently committed suicide in 1945.

Samuel explains to Hans that Nehle looks eerily similar to Fritz Emmenberger, whom he studied with, and who was said to be living in Chile during the war.

The two men start suspecting that Nehle and Emmenberger are the same man, that he committed the atrocities in the concentration camp under the name Nehle, and that he then returned to Switzerland after the war to run his own medical practice.

They start plotting together for how to unveil his true identity, but things do not go according to plan...