Moon Crystals

Natalie Cody has fallen from her horse and is now lost. Her family and the police are all looking for her, but as the weather worsens, concerns for her safety grow. Her twin brother Nathan can sense his sister; with a little help, so can the girl with the moon crystals. The lady who sold them to her told her they were magical, and Alicia Parker is about to find that out when she and her two best friends go on a quest to find the missing girl.
Nathan never loses faith that his sister will be home in time to join him in defeating the evil Carson siblings in the show jumping competition.
Is time really on Natalie's side? Will Alicia's magical crystals help find the missing girl in time to save her life?