Rio (also called "The Kid"), his mentor Dad Longworth, and a third man called Doc rob a bank of two saddlebags of gold in Sonora, Mexico in 1880. Mexican rurales (mounted police) track them, catch them celebrating in a cantina, and kill Doc. Dad and Rio escape, but get trapped on a high ridge with only one horse between them. Rio figures the rurales will be "swarming all over us inside an hour." They decide one partner might succeed in riding to a nearby jacalito (small adobe house) and returning with fresh mounts. They gamble for it, with Rio fixing it so his pal, Dad, can be the one to go.