When Abwehr Captain Eberhard Mock is called from his New Year’s Eve revelries to attend a particularly grisly crime scene, even his notoriously robust stomach is turned. A young girl - and suspected spy - who arrived by train from France just days before, has been found dead in her hotel room, the flesh torn from her cheek by her assailant’s teeth.

Ill at ease with the increasingly open integration of S.S., Gestapo and police, Mock is partially relieved to be assigned to liaise with officers in Lvov, Poland, where a series of similar crimes - as yet unsolved - cast a long shadow over the town.