The Saint agrees to accompany Alan Uttershaw to the airport with a package of diamonds to be handed over to a security firm. However the real security men are killed and the diamonds handed to impostors. Suspicion falls on Gabriel Linnet, partner of the man to whom the diamonds were to be given, but he is murdered and a suit-case containing £100,000 found in his flat. The Saint overcomes the gangsters sent to subdue him and awaits a meeting with the real mastermind behind the robbery.