In the early summer of 1917, Bess Crawford is charged with escorting a convoy of severely wounded soldiers from the trenches of France to England. Among them is a young pilot, burned beyond recognition, who carries a photograph of his wife pinned to his tunic. But later, in a crowded railway station, Bess sees the same woman bidding a heart-wrenching farewell to a departing officer, clearly not her husband.
Back on duty in France, Bess is shocked to discover the wifes photograph in a newspaper accompanying a plea from Scotland Yard for information about her murder, which took place on the very day Bess witnessed that anguished farewell. Granted leave to speak with the authorities, Bess very quickly finds herself entangled in a case of secrets and deadly betrayal in which another life hangs in the balance, and her search for the truth could expose her to far graver dangers than those she faces on the battlefield.