n World War II, a Royal Air Force bomber is forced to crash-land in the North Sea. Among the surviving crew is Commodore Waltby (Michael Redgrave), who is transporting highly classified information on the new, secret German V-2 rockets. An air-sea rescue ship commanded by Officer Treherne (Bonar Colleano) is ordered to rescue the flyers. Treherne battles rough seas and engine failure in a race against time to save the freezing airmen as their dinghy drifts toward the occupied Netherlands.
