In wartime England, circa 1941, poorly-armed tugs are sent into "U-Boat Alley" to rescue damaged Allied ships. An American named David Ross arrives to captain one of these tugs. He's given a key by a fellow tugboat-man -- a key to an apartment and its pretty female resident. Should something happen to the friend, Ross can use the key.

• William Holden
• Sophia Loren
• Trevor Howard
• Bernard Lee
• Oskar Homolka
• Kieron Moore
• Noel Purcell
• Bryan Forbes