Jack Ryan Jr. is on Guam to work on a project for Hendley Associates. It's a perfectly ordinary insurance matter, but trouble finds the Ryans wherever they go. So, it's no surprise when Jack's involvement with a US Navy dive team working off the coast uncovers a threat to international security.
For years, rumors persisted that the Soviets had placed a device for tracking American submarines on the sea floor. By now, the technology should be outdated. But the Americans are still interested in recovering it. It's a seemingly routine mission until they make a shocking discovery: the defensive network they thought they were looking for is actually a weapon unlike anything they’ve ever seen.