In 1865, just after the close of the Civil War, the U.S. Secret Service finds itself at war with Newton's Raiders, a band of cold-blooded killers smuggling guns to Emperor Maxmillian of Mexico. The outlaws operate just outside the U.S. border in Mexico, and when Ed Newton, their leader, kills Frank Baker, the Secret Service agent in charge of the case, Baker's lawyer son Mitch vows revenge.
