Lisa's bratty-cousin Amelia is staying with the Atwoods. The nine-year-old nightmare child is charming around adults, but to other kids, she's a menace! She lies to Max after she causes a stampede at Pine Hollow Stables that almost gets him crushed. Then she breaks the Atwoods' expensive, antique hobbyhorse – and tells Mrs. Atwood it was Lisa's fault.
Amelia is taking riding lessons at Pine Hollow. The Saddle Club plans to give her another kind of lesson, too – the kind Amelia will never forget!