With the special magnifying glass that can be taken out from the cover, the children will have to find secret clues hidden in the pages of this clever book! Help the famous detective Sherldog Holmes to identify the super villain that has stolen the Big Diamond from the Museum!A chase along the city, in different settings (the subway, the research lab, the park...) to collect all the clues and find the guilty of theft. Passing the magic magnifying glass over the pages, the reader will find hidden clues to exclude one of the character from the suspect lists: the games will help children to focus and to develop logic and visual skills.