Set in the small frontier town of Miradero, a 12-year-old girl named Lucky, who had recently relocated from the city, encounters a wild kiger mustang named Spirit. The horse is caught by wranglers and brought to be "broken" in Miradero. Lucky immediately bonds with the stallion, and frees him. Lucky also meets two other girls, Pru and Abigail, who both own horses, Chica Linda, a palomino, and Boomerang, a pinto horse, respectively. They embark on everyday adventures across the land.