Mystery at Malachite Mansion — Carolyn Keene

Nancy Drew and her friends aren't having the most restful Malibu vacation. After noticing pollution on the shores of their beautiful beachfront condo, they check into the shady "holistic spa" next door to investigate a motivational guru who could be tied to ocean garbage dumping! An environmental, ripped-from-the-headlines adventure, with some Kardashian sister look-alikes thrown in. Book two in the Malibu Mystery Trilogy.