Fourteen-year-old Cassy Holt has just moved with her mom and horse to their new home in the Sierra Nevadas when she meets Jonathan Lane, a high school sophomore, fellow horse owner, and detective with a passion for exploring. But one night when Cassy hears the voice of Stardust, a mysterious girl who appears to be in trouble and asks her to find Nanny's cabin, Cassy has no idea she is about to be propelled on an adventure like no other. The next day,...