Tiril, Oliver and Ocho are all geared up for Riverton Theatre’s grand Halloween party. In front of the theatre, a large witches’ cauldron has been put out to be used as part of a fundraiser. Normally, it’s locked shut with a solid padlock. Now however, someone has broken the lock yet left the cauldron brimming with money. So why the effort to crack the lid open? Tiril and Oliver set off to search among scare crows, bats, skeletons, vampires, ghosts, witches, mummies and monsters in order to solve the mystery.