Thomas Kell is a disgraced agent who longs to come in from the cold. When MI6's top spy in Turkey is killed in a mysterious plane crash, his chance arrives ... for Kell is the only man Service Chief Amelie Levene can trust to investigate the accident.
In Istanbul, Kell soon discovers that there is a traitor inside Western Intelligence. Then he meets Rachel - the dead spy's daughter - and the stakes grow higher still.
From London to Greece and into Eastern Europe, Kell tracks the mole. But a betrayal close to home transforms the operation into something more personal. Soon Kell will stop at nothing to see it through.