David and Mary Walls had married, and their life was good. Then suddenly Mary’s father, Bernard Thomes, was killed. She and David began receiving anonymous phone calls asking for a disk belonging to her father. Scared, they decide to ask Otis and Jim Rice, a private investigator and lawyer, for help in finding out just what is going on and with whom they are dealing. Mr. Thomes was in business with some disreputable people—and they want their money and a certain disk back.

Otis and Jim Rice go right to work on the mystery but do not have a lot of clues. The safe in Mr. Thomes’ home is open and supposedly money is missing. Finding out who is calling will take a while, and before long, another murder takes place. Otis has a hint of things to come, but he has no proof.