Revenge by fire - Bill Williams

Trapped in Arizona's worst drought in living memory, Steve Ross has been forced to give up on keeping keep his small ranch afloat. He intends to leave town, but events result in him being given an unusual ultimatum. He must face the prospect of hanging for killing a man or becoming the Deputy Marshal of Craigy Plains. Ross has never owned or fired a pistol, but following his appointment as a lawman, he is taught how to handle a weapon by an old gunfighter. His prowess with a gun is soon given a severe test, and he is drawn into the tragic events that put his own life in the greatest danger.