Campus operative Jack Ryan Jr is in Tehran, when he meets an old friend, Seth. As they part, Seth passes Jack a key, gives him a cryptic message - and vanishes. Now MI6 and the CIA are after Jack. They're desperate to find Seth. Jack tells them he knows nothing - but perhaps he knows enough to find his friend on his own . . . In a dangerous foreign country, chased by agents from all sides, unsure who - if anyone - he can trust, Jack has few clues and no space for mistakes. He's risking everything for Seth. But whose side is his old friend on? And what if it's not Jack's?