The Life and Legend of Wyatt Earp

The Magic Puddle (3x9)

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When the townspeople refuse to let Kate Holliday join their church, Doc comes up with a scheme for revenge. He convinces a couple that the oil puddle they have on the road to Dodge City passing through their land can be used to make a medical ointment. All they have to do is fence it off, and the mule-skinners who use the road aren't happy.