Karl "Curly" Casterline, a wrongfully discharged New York City policeman, finds work on the Midwestern farm of Adolf Bauerle to help the war effort. Curly is attracted to his boss's niece, Mina, but also realizes that Adolf and his cohort, Kurz, plan to blow up a troop train. Curly kills the two saboteurs and saves the train, but he is jailed by the abusive Sheriff Herman Lindig. Although Mina praises Curly for saving the soldiers' lives, he is sentenced to death and is denied a pardon from the governor. After the case attracts national attention, the governor explains that he prolonged Curly's incarceration to draw attention to the danger of German propaganda.
Wealthy diamond collector Larry Hanrahan is given the opportunity to assist the beautiful, jewel-bedecked woman he admires in a Broadway café when she and her guardian are attacked by robbers. Larry is invited to visit the grateful pair, Col. Paul Gascoyne and his ward Adrienne, at the colonel's laboratory, where he is introduced to Wintermute, a chemist who produces imitation diamonds. In return, Larry asks them to view his priceless diamond collection. Although he has fallen in love with Adrienne, Larry is forced to believe that she is a thief when he is robbed by a woman wearing Adrienne's scarf. Larry finds his jewels in Gascoyne's house, but before he can escape, a group of thugs overpowers him. Adrienne assists him in contacting the police, who arrive in time to capture Gascoyne and his gang. Badly wounded, the colonel confesses that Adrienne has been his innocent dupe, whereupon Larry happily takes her to his heart.
When the body of Col. S.F. Hargraves was found in a room in the rear of Cradelbaughs, a gambling house, with a bullet in his heart, the police found "Big Jim" Pemmican, the manager of the place, coolly pacing the floor when they arrived.
A former Annapolis cadet is thrown out of the Naval Academy for cheating on an exam. Of course he was framed, but he must enlist in the Navy to clear himself. Meanwhile he and his sweetheart search for a buried treasure on Lost Island, which everyone is after.
Virginia Chester visits her Aunt Betty who resides near an army post. Lieut. Calhoun falls in love with Virginia, and after a whirlwind courtship persuades her to marry him secretly. Helen Brassey, the daughter of the Colonel, is in love with Calhoun, and gets her father to help her win the lieutenant's affections.
