“I do have one piece of useful intelligence,” said Freddie. “Guy Chesterton’s out.”

Adam White, British ambassador in Oslo, is shocked to learn that the man who tried to kill him fifteen years earlier in Oxford is out of prison and seeking revenge.

In the same week, MI6 officer Hugh Tennyson informs Adam that a man murdered on an Oslo train is Leonid Zabolotny, a Russian FSB agent claiming knowledge of a mole in the Norwegian security service (the PST) and of an unspecified threat to British security. Hugh joins Oslo Police detective Rebekka Storvik in the hunt for the killer.

Others soon involved are Adam’s lover, Alison Webster, the former Oxford student Taraneh Esfahani and her onetime MI6 handler, Freddie Gardiner, a sworn enemy of Hugh Tennyson.

How and when will Chesterton strike? Who is the PST mole? What is the threat to British security? The Deputy head of the PST, Holger Selberg, is arrested, but protests his innocence. Has he been framed? If so, who by? There is no shortage of suspects, and any number of twists and turns, as the intertwined stories come to a series of unexpected climaxes.