Tom Clancy: Pressure Depth (hardcover) by Jack Stewart

Some secrets are best left at the bottom of the ocean. But since that’s not in Jack Ryan, Jr.’s nature, he’ll battle all of China to stop them from finding a weapon of immense destructive power in the latest entry in the #1 New York Times bestselling series.

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 By now, the technology should be outdated.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.