Bonanza (1959)

S4E5 The Deserter

Colonel Edward J. Dunwoody, a man with a deep disdain for Native Americans, arrives at the Ponderosa searching for Bill Winters, an army deserter and close friend of the Cartwright family. Unbeknownst to the Colonel, Bill is his son and is married to a Native American woman. Bill fled after receiving orders to commit a horrific act against the Shoshone by poisoning their food and water, a plan for genocide. When the Shoshone learn of this, they capture Colonel Dunwoody in retaliation for his son's actions.