The two eternally boozing and brawling U.S. Marines, Captain Flagg and Sergeant Quirt are inveterate romantic rivals on peacetime assignments in China and the Philippines. Flagg and Quirt duke it out over the affections of the saucy Shanghai Mabel. 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. They continue their private war as all hell breaks loose around them. When they do not have to fight, Flagg and Quirt are vying for the attentions of coquettish Charmaine. After a heavy battle, Flagg and Quirt both decide to go AWOL for the sake of Charmaine, but when duty calls, the two friendly enemies march shoulder to shoulder towards new adventures.