The lazaret ship Britannic is used by England to transport weapons to Egypt. The German secret service wants to show that abuse of the red cross by overtaking the ship and steering it to a neutral port for inspection. The British secret service hear rumors of an operation and places its own agent, Vera Campell, a board, using the false identity of the nanny of the wife of the British Ambassador in Greece. The German plot to overtake the ship fails, so does a torpedo attack by a submarine. Will the ship be captured?