A spy known as "1932" during World War I, is commissioned by the German Secret Service to trail English agent Captain Woodhouse to the Straits of Gibraltar and there effect the destruction of the British fleet. Before his departure, 1932 helps Jane Gerson, an American girl falsely accused of espionage, and later falls in love with her. In Egypt, 1932 secures Woodhouse's clothes and identification and proceeds to Gibraltar. The governor of Gibraltar is led to suspect "Woodhouse" by British agent Billy Capper and Jane, who is his house-guest. In the end, Jaimihr, a Turkish servant employed by the governor, is revealed as the true German agent, and 1932 is identified as Captain Cavendish of the British Intelligence Bureau, who is now free to turn his attention to Jane.