Fury of the Mountain Man — William W. Johnstone

Six-Gun Justice. . .
Smoke Jensen was the last mountain man and the quickest draw in the West. But he was tired of fighting every punk who wanted to make a reputation for himself, so he hung up his .45s.

It Didn't Last Long. . .
Like Jensen, the two Mexican gunfighters known as Carbone and Martine had put away their six-guns, married and turned to ranching down in Durango. Then they came up against an army of outlaws under a warlord who called himself Carvajal. That was when they called on Smoke Jensen. Smoke didn't waste a minute. When your friends called, you came running. Carvajal laughed when he heard that Smoke Jensen was on the way. After all, what could one man do?"