Join Dennis, Gnasher and friends on a school trip like no other! Twelve school kids One evil mayor One mad scientist One forbidden dog A mystery afoot The Natural History Musuem won’t know what hit it! Class 3C are on a school trip to London, thanks to Rubi winning an award for her science project. However, it’s not long after arriving that pieces of dinosaur skeletons start to disappear from the museum … and who better to blame than Dennis’s bone-loving companion? Can the friends solve the mystery of the missing bones and get Gnasher off the hook before something terrible happens?