Clio has already had one brush with the paranormal and she's dead set on making it her last. But her new babysitting job is in a haunted house! At first, Clio's excited to work at the Victorian mansion in town - until doors start closing behind her, objects move on their own, and messages appear from beyond the grave.

When a valuable diamond necklace is stolen, it is up to the Gemini Detective Agency--twins Zach and Evie Mamuya and their friends Vishal Desai and Sophia Boyd--to investigate; clues to the mystery are included in the illustrations throughout.