Plot

The Highlanders and Lowlanders are sworn enemies until Lieutenant Kemper, the son of Brigadier Kemper, the leader of the militaristic Lowlanders, is held hostage by the Highlanders until his father's army has retreated to its own boundaries. Much to his surprise, the lieutenant is treated with kindness and consideration by his captors, especially by Boyadi and his beautiful daughter Nathalia, whom he learns to love. Thus, instead of obeying his father's command to escape at an appointed time when the Lowlanders plan to violate their pledge and storm the fortress, he keeps his promise to his captors and remains a prisoner. The Highlanders, inflamed by the Lowlander's broken word, are about to kill the lieutenant when news comes of the approach of another foe and, hailing the Kempers as saviors, the two former enemies unite to defeat this new foe.

Brigadier Kemper, at the head of a division of Lowlanders, has invaded the peaceful country of the Mountaineers. Caught in a bad position, he is forced to give his only son, Lieutenant Ivo Kemper, as hostage for the good conduct of the invaders on their retreat. The brigadier means to violate the truce, so he persuades his son to carry a dirk concealed on his person and warns him to be prepared, on a given night, to make good his escape from the Mountaineers. Turned over to the custody of Boyadi, one of the Mountaineer leaders, Lieutenant Kemper is prepared for mistreatment at the hands of those whom he looks upon as savages. Instead of that, however, he finds Boyadi all that is considerate and kindly, and after some preliminary skirmishing he becomes much interested in Boyadi's daughter, the beautiful Nathalia. The night appointed for his escape comes speedily, but Lieutenant Kemper realizes, to his horror, that he can escape only by killing Boyadi. This he cannot bring himself to do, so he finds himself the next morning a prisoner at the hands of the outraged mountaineers, who are furious at the treachery of his people. Moreover, he himself is in disgrace, for the dirk has been discovered in his possession. At this seeming proof of his treachery, even Nathalia turns away from him. In the effort to make him reveal his father's plans, of which he is entirely ignorant, by the way, the mountaineers put the young Lieutenant Kemper through a pretty rough sort of "third degree." He is saved at last only by the interference and protest of Boyadi and the fact that he behaved himself with credit while he was with the army of invaders. On these grounds he is reprieved for twelve hours before his execution, and allowed to take a farewell of Nathalia, who had come to look more kindly upon this young man who had proven himself so courageous under the terrific torture he had undergone. Brought out for execution at the appointed time at dawn the next morning, and stood against the firing wall. The men are about to shoot when a messenger brings word that the lowlanders and the mountaineers have declared peace in order to fight together against a common enemy. Lieutenant Kemper is not only freed by this peace movement, but becomes a kind of hero to the very people who had been about to spill his blood. He returns in triumph to the waiting Nathalia to whom each moment since his departure had been agonies of torture, and the two are made happy at last.