A secret spy threatens St Smithen's, and Poppy Pym must solve her most difficult mystery yet!

When a mysterious runaway van crashes into St Smithen's on the first day of the new school year, Poppy knows it's going to be an action-packed term! But when accidents continue to happen at St Smithen's, Poppy can't shake the feeling that her every move is being watched.

With the Christmas holidays looming, secrets lurking in every corner and rumours of a dangerous beast on the loose, Poppy must unravel her biggest mystery yet.

Can Poppy unmask the hidden spy before someone gets hurt?