Shootout at Sioux Wells (U)

Zack Keech's business was cattle; railroads were a nuisance, an interloper on the free range and a pain in Zack's saddle-tanned anatomy. So how did this rootin'-tootin' cowboy -- who only wanted the money he figured was due him for a train-triggerd stampede -- find himself working as an undercover agent for two most unusual railroad owners and the notorious Wild Bill Hickok? And furthermore, what was he doing in a situation where not only were a lot of self-declared enemies out to gun him down but even his supposed friends had to pretend that he was an outlaw and a man that Sioux Wells would be better off without?