In the sequel to Gunner, detective Joseph Gunner is plunged into a world where no one can be trusted and nothing is what it seems.

New York, December, 1941. A city preparing for war. Troop ships and trains full of young conscripts arrive every day. All of them set on one last party before being sent overseas. The bars and clubs are packed. Every night is like New Year's Eve.

Gunner and Nickerson are working for the BSC, a section of the British Secret Service tasked with covertly encouraging pro-war sentiment. They are stationed at the Hamilton Princess Hotel, a huge censorship operation. Every wire, parcel of mail, or radio broadcast to Britain is listened to for coded messages.

When the head of the Japanese intelligence section is murdered and his flat ransacked, Gunner tries to find out why. Who needed to silence the victim? As the investigation continues, he finds some messages aren't being intercepted after all. There's a traitor in their midst. A traitor prepared to kill.

As the clock ticks down towards the 7th of December, Gunner races to solve the crime before he becomes the next victim.