The first adventure of David Callan, top agent for the S.I.S. Forcibly "retired" several years earlier because he had lost his nerve, Callan is called back into service to handle the assassination of Schneider, a German businessman who may be more than he seems. This TV movie lead the way to a TV series, entitled "Callan", and the same story was later adapted into a theatrical film, also entitled "Callan".