August 12, 1886 - Former bank robber Sam Colby and his two partners intend to ambush and rob an army payroll wagon using a stolen Gatling gun. After setting their trap, Colby rides into Tombstone to purchase as much ammunition as he can and comes into contact with Harris Claibourne and his former fiancé Sarah Medford. Colby's violent actions bring him to the attention of Sheriff Clay Hollister who has serious concerns about Colby and the real reasons behind his visit.