Mount Emily: Book 1 - Mount Emily, #1

While digging around their school's backyard in search of an urban legend, Patsy Goh and her best friend Elena are whisked back in time to 1987. Trapped in their mums' 13-year-old bodies, the duo race against the clock to hunt down the magical time crystal that got them in this mess, before the evil Midnight Warriors find it and cause a time crisis that could destroy all of existence.