Jim Grant, range boss of the Swinging J, was in Lafe Haskins' way, threatening the elaborate scheme Haskins had conceived when he had learned that old Joel Collison was leaving the Nucces River country to move to the Rio Grande valley. So Haskins planned to kill Grant, and then take his chances with the law - such as it was. However, Grant outsmarted and outflanked him and, instead of being shot, cut off Haskins' trigger finger, which left him not seriously hurt but without the power to retaliate. But that didn't stop Grant's and Collison's troubles. Longhorns were being rustled, and their trail mysteriously disappearing at the water's edge - and cows cannot swim!.