The Cartwrights' neighbor Tom Edwards has lived as a paraplegic, ever since an accident involving Ben Cartwright and a gun. His ranch is going to waste. His wife Joyce is a longtime friend of Ben, and Ben decides to help the Edwards couple by making Tom a business proposition: the Cartwrights will build a grain mill on Edwards' land. In return, Ben only wants his investment money back, plus fifteen percent. Tom and his hired hand Ezekiel are suspicious of Ben, but Tom agrees to the deal. The Cartwright men build the mill, but tension begins to rise when Ezekiel makes comments which rekindle Tom's suspicion.

Ranchers are being killed, cattle stolen, and retired U.S. Deputy Marshall Denver McKee leads various posses after the suspects but never seems to be able to find them. In the meantime, McKee seems to have plenty of money to take care of his gorgeous daughter back home from schooling in the East.