Callie wishes that her special summer with her ghost horse Star, who only she can see, will never end. Being new in town, she is unsure of herself when school starts. Star gets sick and she becomes visible, while Callie starts fading.
The ghost horse, Star, returns to Callie on a trail when she is jealous that Callie is riding another horse, but Callie calms Star's fears, and helps to reunite Star with her ghost owner Michael.
On Callie's first night in Arizona, she looks out her window and sees a ghost horse, named Star. Star is a beautiful grey mare and Callie is just longing to find a way to ride him and learn why he is appearing only to her.