Twelve-year-old orphan Margret and her older sister, Libby, are staying with the kind Mrs. Fredriksen in her sod house in Littleton, Colorado. Margret knows that Libby, with her basic distrust of anyone, will have them moving along soon enough, but Margret wants to stay. When a tornado sweeps through, bringing with it an injured horse, Margret lays claim to the animal, naming him Flynn, nursing him back to health, and teaching herself to ride. Now more than ever, Margret yearns for some stability in her life. Somehow she must convince Libby to stay so she can make Flynn hers.