Max and Lia's underwater adventure concludes in this thrilling series by Beast Quest author Adam Blade! Max and Lia have tracked the evil Professor to his lair in the Black Caves. Neither of them are ready for what awaits them there. Kraya the Blood Shark, with his razor sharp teeth and laser cannons is the most vicious of all the Robobeasts. Max must survive if he wants to finally come face-to-face with the Professor to save his father and retrieve the fourth and final piece of the Skull of Thallos. But there are still some secrets Max has not uncovered, and they could lead to Max's defeat.