An old school friend of Detective Sergeant Alistair MacRae of the Lothian and Borders Police appeals to him for help after he and his girl friend are subjected to a series of harassing incidents. MacRae is able to ensure that the harassment comes to an end and, in the process of doing so, is led to the identity of the person who can tell him where an infamous fraudster is enjoying his ill-gotten gains. Along with Detective Chief Inspector Ian Forsyth, he goes to arrest the fraudster only to find that the man is dead after apparently being subjcted to violent torture. MacRae and his squad arrive at the name of the man that they think is responsible for that and another death. But Forsyth shows that they have got it wrong and, by the use of logical deduction, is able to arrive at the name of the guilty party.