Three years ago, wealthy heiress Xandra Collins vanished without a trace, leaving her 100-year-old mansion abandoned. One mind-bending clue was hidden underneath the velvet lining of her jewelry box: GL URMW NB WR@+B, BLF NFHG TL Y@XP GL GS% SRWW%M U&LL+Thirteen-year-old detective Skylar Robbins moves into the multi-level mansion with her family and immediately takes the case. The heiress’s body was never recovered. A sinister stalker mentioned in her diary may have been a close relative. Or was a perfect stranger to blame?Pacific Middle School bullies label Skylar’s detective agency a joke. Skylar and her assistant detective Alexa must decode the secret message in time to crack a new case and save their reputations at Pacific. They team up with Daniel Gannon—the most brilliant boy in middle school—to solve the mystery of the heiress’s disappearance.Decoding the message opens the door to a world of danger. Now Xandra’s stalker is after Skylar! The team uses their detective tools and sleuthing skills to piece together a complicated puzzle. Inside the mansion, a trap door leads to a secret passageway. Skylar’s ultraviolet light illuminates a shocking mural, painted on the wall inside a hidden floor. Poems in Xandra’s diary contain clues that lead to a mysterious key. Skylar and Daniel must brave life-threatening waves and menacing enemies to locate the lock. Can they determine how the heiress went missing…before Skylar suffers the same fate?