U.S. Marine sergeants Quirt and Flagg are inveterate romantic rivals on peacetime assignments in China and the Philippines. In 1917, W.W. I brings them to France, where Flagg, now a captain, takes up with flirtatious Charmaine, inn-keeper's daughter. Of course, Quirt has to arrive and spoil his fun. But the harsh realities of war and the threat of a shotgun marriage give the two men a common cause...