Mackenzie's Raiders

The Poisoners (1x24)

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When a rancher imports a herd of short-horn cattle onto the Texas range near Fort Clark, his neighbor, a cattle baron who runs only longhorns tries to drive him out - first by persuasion, then by running off his stock, then poisoning his waterholes and finally by murdering his men. Mackenzie sets a trap for the crooked rancher by pretending to be an Eastern reporter who is in possession of incriminating photographs.