Carl Pfeiffer and Henry Block, who emigrated from Germany to the United States, have become prosperous and argumentative. When the World War breaks out, Henry is one hundred percent American while Carl's loyalties are divided between his adopted country and his native land. William Pfeiffer, Carl's son, enlists in the U. S. Army, deeply disturbing his father, who is persuaded by Miller, a German agent, to contribute money to the German cause. Miller uses the money to place a saboteur on the troopship to which William is assigned. The saboteur disables the ship, and Carl receives a report that as a consequence William has been killed. William turns up unharmed, however, and Carl and Henry set out to capture Miller with the help of Hilda Schwartz, a Secret Service agent. After Miller is finally captured, William marries June Block, Henry's beautiful daughter, with the happy consent of the old friends, who now agree completely in their loyalty to the United States.