With the excitement of summer camps over, Rosie and Carrie work to get their horses in shape for the state 4-H competitive trail ride. The girls are surprised to learn that Abigail, the arrogant new boarder at Sonrise Stable, is also entered in the race. Can Scamper and Zach keep up with her flashy Arabian? How much is Rosie willing to risk in order to beat Abigail and win the competition?

Rosie and Carrie have talked off and on throughout the series about creating their own book together. Book 7 includes an original story written by Carrie and illustrated by Rosie!