The story follows 16-year-old amateur sleuth Kay Tracey as she faces a mix of superstition and real-world danger.

A fraudulent spiritual medium named Cara Noma attempts to place the "Green Cameo curse" on Kay after Kay exposes her scams. Shortly after, a young bride-to-be vanishes from Lotus Gardens, the estate owned by a wealthy family, the Wongs. Alongside her best friends, Wilma and Betty Worth, Kay uses a distinct green cameo heirloom as a vital clue to track down the missing girl. Kay must dodge a dangerous ring of lawbreakers while constantly dealing with interference from her jealous school rival, Ethel Eaton.