Ex-MI6 officer Paul Samson has been tasked with secretly guarding a gifted young woman, Zoe Freemantle. He is just beginning to tire of the job when he is attacked in the street by a freakish looking knifeman. It's clear the target is on his back not hers. What he doesn't know is who put it there.

At that moment, his mentor, the MI6 legend Robert Harland lies dead on a remote stretch of the Baltic coastline. Who needed to end the old spy's life when he was, in any case, dying from a terminal illness? And what or who is Berlin Blue, the name scratched in the sketchbook beside his body?

A few hours later, Samson watches footage from the US Congress where billionaire philanthropist Denis Hisami is poisoned with a nerve agent while testifying - an attack that is as spectacular as it is lethal, but spares Anastasia Hisami, the love of Samson's life.

Two things become clear. One, it was a big mistake to lose the mysterious Zoe Freemantle. And two, Robert Harland is making a final play from beyond the grave.