Vietnam veteran Robert Bellamy now with U.S. Naval Intelligence is sent to find ten witnesses to the crash of a weather balloon in Switzerland, which had carried secret equipment.  This has been recovered, but the witnesses must be sworn to secrecy.

However, he finds that he himself is being hunted by an unknown lethal force, and that what he has been told about the balloon was only part of an incredible story.

The tale swings from Washington DC to Zurich, and Bellamy's past is brought to the fore, and he also finds out why the secret of the balloon must never be revealed to the world.