New Year's Eve, 1919. Scotland Yard's Inspector Ian Rutledge has accompanied his sister to the home of mutual friends for dinner but is called away by work. On the steps outside, he finds a brass cartridge casing that is seemingly identical to the countless others he'd seen during the war he still cannot forget. But this one has an engraving in the metal. Curious, he pockets it. Soon he finds another -- in a most unexpected place.

These cartridge casings seem to point to unfinished business involving the war. A man with a dark secret, Rutledge already walks on the edge of sanity. Now someone is hunting him. But who? And will Rutledge live long enough to discover why?