Cynthia, heiress of Adams Group, was once the “Demon” who terrified the underworld. To fulfill her mother’s dying wish, she put away her guns and posed as a socialite. Seven years later, her fiancé Byron and Janet humiliate her in public—so she stops pretending. She summons the Black Hawk Guard, exposes their affair and embezzlement, unravels Janet’s family revenge plot, and sends all three to prison. Byron escapes, allies with Mitchell, and plots to bomb the group’s gala—only to be trapped by Cynthia and sentenced to life. Mitchell proposes a merger, is refused, and kidnaps Betty to force Cynthia to come. Cynthia leads her team, saves Betty, kills Mitchell, and finally returns to peace.