It's 1943 and Lily Tregenza lives on a farm in the idyllic seaside village of Slapton. Apart from her father being away, and the "townie" evacuees at school, her life is scarcely touched by the war. Until one day, when Lily and her family, along with 3,000 other villagers, are told to move out of their homes: lock, stock, and barrel. Soon, the whole area is out of bounds, as the Allied forces practise their landings for D-day, preparing to invade France. But Tips, Lily's adored cat, has other ideas; barbed wire and keep-out signs mean nothing to her, nor does the danger of guns and bombs. Frantic to find her, Lily makes friends with two young American soldiers, who promise to help her. But will she ever see her cat again? Lily decides to cross the wire into the danger zone to look for Tips herself.