David Callan, top agent/assassin for the S.I.S., was forced to retire because he had lost his nerve. Now, Callan is called back into service to handle the assassination of Schneider, a German businessman. His former boss promises Callan that he`ll be returned to active status if he follows orders, but as always Callan refuses to act until he knows why Schneider has been marked for death. This film is a remake of the same story presented in "A Magnum for Schneider."