An Eastern Bloc courier is shot and captured at an airport while entering the U.S. The courier had hidden tape intended for a mysterious operative known only as "Alexander." Erskine goes undercover, taking the place of the courier. He quickly discovers the situation is more complicated than he imagined. The FBI inspector is now in the middle of an espionage ring with conflicting allegiances. Alexander is loyal to Moscow, while other members now are loyal to China. On top of that, the courier Erskine is portraying was hired to kill Alexander. Colby and other FBI men can only keep track of the FBI inspector from a distance.