In a short prologue, Gunpowder Wetherill, a millionaire chemist, discovers the formula for making noiseless gunpowder and at once telegraphs Washington of his success. The War and Navy Departments tell him to take the formula and proceed to Hampton Roads, where all tests will be made. The secret of the discovery is closely guarded. But an indiscreet young under-secretary lets slip a stray word to a reporter regarding the new discovery and the newspapers seize upon it and make it public. Into an international conspiracy to rob Wetherill of his formula is thrust Hope Flannigan, a little slavey employed as a dishwasher in a small Sixth Avenue restaurant conducted by Gaston, a spy employed by a foreign government. He and his woman confederate, La Belle, receive instructions to gain possession of the formula. Wetherill has a daughter, Irene, and Gaston determines to obtain the formula and marry the daughter as well.