Arizona sheriff Sam MacKenna (Gregory Peck) thinks his luck is in when he is given a map to a mythical 'Valley of Gold'. But the news of the map travels fast, and soon everyone wants a piece of the action, including the brutal bandit Colorado (Omar Sharif). Colorado captures MacKenna and forces him to lead the way to the valley, but as they approach their goal, an increasing number of desperate treasure hunters join the hunt, and the chances for betrayal and treachery grow accordingly.