Jack Ryan Jr. is on Guam to work on a project for Hendley Associates. His 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 By now, the technology should be outdated.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. That explains the arrival of a Chinese special operations team who seem determined to get their hands on the aging tech, even if they have to kill to do it.

Charley Castillo, the original Presidential Agent, is in Virginia Beach to visit his son when two gunmen appear. Charley is able to thwart a deadly mass shooting, but he is hit and badly injured. Meanwhile, Pick McCoy is at the Naval Academy catching up with some old friends. When news of the attack reaches him, he senses that this is no random event. While Charley clings to life, Pick searches for the men responsible and in the process uncovers a deadly plot that threatens to strike deep at the heart of American democracy.