Two long years after the outbreak of the American Civil War, Richard Gatlin, the creator of his devastating machine-gun namesake, offers his invention to the Federal Government. As a result, President Abraham Lincoln secretly sends a commission to the dusty town of Las Cruzes, New Mexico, to pick up the weapon and escort him back to Washington. However, in the middle of the night, two assassins kill the team and kidnap Gatlin. Now, Captain Chris Tanner, of the Pinkerton Agency, finds himself unjustly accused of high treason and faces death. Who is behind the audacious theft? Will the wrongfully accused agent manage to find the culprit and clear his name?