Twin brothers Dominic and Brian Caruso, respectively a rookie FBI agent and a Marine just back from Afghanistan, are recruited, along with their cousin Jack Ryan Junior, to a top-secret anti-terrorism organisation.
Jack's father, U.S. President John Patrick Ryan, has appeared in other Clancy novels (and their screen versions, played by Harrison Ford and - in an improbably youthful incarnation - Ben Affleck), and Junior is at least as smart as his dad.