Murders take place and each crime is similar to the last. One person must have committed them; but who? Another attack. The victim survives but has amnesia and is the only person who can make an identification. A suspect is arrested.

Hardy is trying to piece together the burnt pieces of paper found in the suspect's room. Jo has been asked to try and break the surviving victim's amnesia by hypnosis. The suspect is questioned at length. The case builds up against him.