When Nathaniel McBain and Shackleton Frost arrive in Lone Pine to escort a prisoner to Beaver Ridge jail, they are shocked to discover it is Shackleton's old friend Sheriff Ashton Clarke. Five years ago Ashton tamed the town, but now he's been charged with killing in cold blood.

Ashton claims that someone from his past has framed him, and Shackleton believes his friend. But as more bodies are found with all the evidence pointing to Ashton, the case against him begins to look unbreakable. If Nathaniel and Shackleton are to solve the mystery and save their friend, they will have to turn their backs on their duty and use their trusty six-shooters instead.