Robin Cameron transforms her home on the Scottish seacoast into a hospital for convalescing soldiers. Sidney Carson, who owns the adjoining estate, and Dr. Hyde both love Robin, but she gives her heart to John Hamilton, an American soldier whose ship was sunk off the coast. When several Allied officials are sent to investigate reports of German spy activities in the area, an air raid occurs, and one of the officers is almost killed. Carson accuses John, and Dr. Hyde, jealous of the American's success with Robin, supports Carson's claim. With the aid of a little Belgian girl named Mimi, however, Robin discovers that it was Carson who had sent nightly messages to a fleet of German submarines. Exonerated, John departs for the front, and Robin, although her younger brother Donald has just lost his life in battle, bravely bids him farewell.