Jack, age 11, has always wanted to be a cowboy. Now he has his chance to "ride fence" on a big ranch for the summer. As he learns to ride and rope, he encounters Ann, a bright-eyed redheaded girl his same age. She calls him a Tenderfoot Dude and laughs and teases him. On the trail, he meets scorpions and rattle snakes. A kidnapping has to be solved, which pushes Jack to his limit.