London, December 1942. As the Russian army repels German forces from Stalingrad, Maggie Hope finds herself living dangerously as a spy. When she's called upon to look into the theft of a Stradivarius, one of the finest violins ever made, Maggie can't resist. Meanwhile, there's a serial killer on the loose in London, targeting conscientious objectors. Little does she know that investigating this dangerous predator will pit her against a new evil, and old enemies.