During the Second World War, an American pilot stationed in England meets a young British nurse during an air raid on London. The two instantly fall in love, despite the fact that the young nurse is already married, a secret she keeps hidden from her American lover. After being shot down behind enemy lines, while being assigned to ferry a British agent into France, the American pilot realizes that his secret cargo is in fact his lover's husband, and that the two must now work together in order to survive.