*A missing Chinese scientist, unexplained noises emanating from under the Arctic ice, and a possible mole in American intelligence are just some of the problems that plague President Jack Ryan in the latest entry in Tom Clancy's #1 New York Times* bestselling series.**

Aboard an icebreaker in the Arctic Ocean a sonar operator hears an unusual noise coming from the ocean floor. She can't isolate it and chalks the event up to an anomaly in a newly installed system.

Meanwhile, operatives with the Chinese Ministry of State Security are dealing with their own mystery--the disappearance of brilliant but eccentric scientist, Liu Wangshu. They're desperate to keep his crucial knowledge of aerospace and naval technology out of their rivals' hands.