The past won't end

A few years back Frank Nolan had killed a man in New Mexico Territory. That man had been killed in self defence but Nolan had to leave in a hurry none the less. Now studying medicine in Massachusetts he reads that the Territory papers are saying that he was back and had killed three other men in the same way. Someone was using his name and reputation for evil ends. No matter what the consequences Nolan knew he had to return to the Territory to face his past and find out who was killing these men -- and why.