From New York Times bestselling author Joanne Harris comes a richly imagined and captivating novel of two colliding worlds.

Deep in the heart of London, a photographer walks the streets and captures whatever catches his eye: an old man drinking coffee; a beautiful woman sipping champagne in St. Pancras station; a cloud of moths, disturbed, taking flight across the sky.

But with each photo, he captures something unseen by the eye, and as each negative develops—revealing a person he hadn’t met, a danger he hadn’t noticed, and a world he hadn’t seen—he is drawn further into a hidden war. One which he has been drawn into many times before...and every time, had his memories of the truth, and of the woman he loves, stolen from him.

As Tom pieces fragments of the truth together, he realizes he must weave through the war and fight his own battle: both for the woman he loves, and for himself.