In 1938, eighteen-year-old Helen Douglas leaves Berwickshire for Normandy, to work as a governess for a young Jewish family. But as World War Two breaks out and the chateau belonging to the family is requisitioned by the occupying German army, Helen finds herself trapped in a dangerous situation. Forced to take on a new identity to protect those entrusted to her, Helen must keep her activities hidden from her German employers. But as she grows ever closer to the charismatic General Karl von Werstein, bonding with him over their shared love of music, Helen becomes increasingly tangled in a web of lies and intrigue, forcing her to make decisions that test the very limits of her morality.