Carl Ranke, an Italian inventor, after a series of dangerous experiments, discovers a new high explosive which, after being tested by the Italian Government, gives them the assurance necessary to enter the great conflict. At the reception given by His Highness, Ranke falls in love with the daughter of Colonel Colonna, and in keeping an appointment with her is kidnapped by the Austrian spy. Captain Otto Senza, who is serving in the Italian Army. He is imprisoned in the little magazine Fort B2 and is given the choice of revealing his secret of the formula or death, but he, game to the last minute, though death is staring him in the face, prefers to sacrifice his life rather than betray his country. He is saved from the very jaws of death by his faithful dog, and the despicable Austrian meets the death intended for his captive. Sylvia tries to save him but only succeeds in getting into the toils of the spy and sees from her cell window, as she thinks, the death of her lover. After a series of adventures, Ranke succeeds in getting back to his own country just in time to marry the girl who has been faithful to him, in her heart, all through his trying experiences.