Oz Chambers has a wonderful secret, the obsidian pebble, gifted to him by his dead father, is an artefact of astonishing power. The sort of power that makes the year eight science project a hands-down walkover thanks to the the pebble's genius avatar, Soph. But, there are sinister forces abroad who will do just about anything to get their hands on the pebble, and when fellow pupils start being attacked, Oz finds himself in very hot water. Soon Oz and his friends, Ruff and Ellie, are caught up in a centuries old mystery involving a missing ring, lava toothpaste and a murderous monster known as the Beast of Seabourne