Capper Stevens, a well-educated man-about-town, runs a counterfeiting ring.  Using his girl friend, Aimee Maxwell, as a decoy, he kidnaps U.S. Treasury Department engraver Tom Perkins and forces him to make money plates.  When Aimee's sister Verna is evicted from her apartment, Aimee goes to help her, and while they are in Aimee's car, they are held up by a man who demands her purse.

Just then, a police car spies the holdup and arrives on the scene, but Aimee, knowing her purse carries counterfeit money, tells the officer that the thief is actually a friend.  The police become suspicious, however, and trail Aimee's car, causing the thief, whose name is John Madden, to ambush the patrol car, apparently killing its occupants.  In reality, however, the holdup and the ambush were staged by John, who is really a secret service agent trying to infiltrate Stevens' counterfeiting ring.  The ploy works, and Aimee takes John to gang headquarters, where Stevens welcomes him, believing he is a killer.

Later Stevens captures a federal agent and orders John to kill him, and John fakes the murder.  Meanwhile, Stevens keeps Verna a prisoner, fearing that she will go to the police if she is released.  By now, John loves Verna, but is reluctant to reveal his true identity.  In Washington, DC, federal agents lay the groundwork for capturing the counterfeiting ring, to which Treasury agents have traced nearly a million dollars, although the exact location of the plant that prints the bills is as yet unknown.

When agents arrest "passers" of the fake money, Stevens moves his gang to a country estate, where the bills are printed, and John is held captive and is unable to report to Washington.  When Verna becomes hysterical, Stevens orders John to kill her during a hunting trip.  John signals a passing army plane, giving them the location of the plant, and asks them to expedite the arrests.  Just as John is about to fake Verna's death, the Treasury agents arrive and raid the hideout.  Aimee is killed in the melee, and John is wounded, but Stevens and his gang are captured.

After he returns to Washington, John makes a plate for an engraved wedding invitation to his and Verna's wedding.