Grace Lamont
Quirky chemist Eben Lamont has discovered a powerful new explosive and plans to turn it over to the government. Richard Leslie, the head of an explosives manufacturing company, offers to buy his new discovery, but Lamont turns him down. Afraid that his formula will be stolen by Leslie, Lamont uses invisible ink to tattoo part of the formula on his daughter Grace's shoulder. A spy for a foreign government finds out about it, kills Lamont and kidnaps Grace, hypnotizing her so she'll tell him where the formula is. She is rescued by Leslie in the nick of time, but her troubles, as it turns out, are not yet over.
Madelyn Forrest
Shortly after Dr. Allen Forrest, who is involved with aircraft production for the United States government, invites his young nephew and business partner, Leonard White, to live in his home, idle gossips begin to spread rumors about Leonard and the doctor's pretty wife Madelyn. At first, Allen refuses to believe the stories, but gradually he becomes suspicious. One night, the doctor hears a noise in Madelyn's room, and when he rushes in, he is shot in the arm. The young man jumping from Madelyn's balcony resembles Leonard, and the doctor, deeply hurt, accuses his wife of infidelity. Madelyn is on the verge of killing herself when a secret service agent appears, reporting that the German spy who attempted to steal secret documents from the doctor's home the night before had been apprehended.
