A teenage couple having a rendezvous on a beach in Florida are suddenly interrupted by a submarine emerging from the ocean. Armed soldiers disembark from the vessel, and a Buick drives off its landing ramp. For Henry Hazen, who is scheduled to ship out to an army training camp the next day, the sight leaves him uneasy, but he tells no one.

Katharine Hume is the only woman working for the Pentagon’s Atomic Energy Commission. She and her team are convinced the Russians are poised to conduct a nuclear attack against the United States. But convincing her superiors an attack is imminent is proving more difficult than she could have imagined—even after several stealth fighter planes and their pilots disappear over the Gulf.

Banker Robert Gumol sees all the signs that the big attack is finally coming. As a reluctant spy for the Russians, Gumol’s loyalties lie more with his adopted country than his motherland. Deciding to take the next flight to Havana, he risks being executed by the Russians if his betrayal is discovered—but he’s willing to put it all on the line for a chance at freedom.

With the clock ticking, the fate of America hangs by a very thin thread.