During World War I, John Stevens invents an anti-submarine device, but the plans are stolen by two German spies, the Baron von Wiederholtz and Madame Elsa, who flee to a New York hotel. Stevens' daughter Alice pursues the spies hoping to retrieve the plans.
| Actor | Role |
|---|---|
 Winifred AllenAlice Stevens | Alice Stevens |
 Earle FoxeHoward Skeele | Howard Skeele |
 Forrest RobinsonJohn Stevens | John Stevens |
 Robert FischerBaron Kuno Von Wiederholtz | Baron Kuno Von Wiederholtz |
 Margaret GreeneMadame Elsa | Madame Elsa |
 Clarence HandysideRichard Skeele | Richard Skeele |
| CCharles WellsGeorge Worth | George Worth |
| MMadeline MarshallMargaret Worth | Margaret Worth |
| AAmy SomersFrench Maid | French Maid |
| RRiley HatchHouse Detective | House Detective |