For the Mastery of the World.

US secret service agent Mr. Grimm is hot on the trail of spy Rosa Morini and her brother Prince Morini who are planning to sell a remote-control wireless bomb apparatus which if it falls into the wrong hands will make its possessor the master of the world's power. Rosa manages to elude capture at first but after the death of her brother sees the error of her ways and a crisis is averted.