Razi, a local fisherboy, is watching turtle eggs hatch when he sees a boat bobbing into view. With a chill, he notices a small, still hand hanging over the side. Inside is Zheng, who's escaped a shipwreck and is full of tales of sea monsters and missing treasure. But the villains who are after Zheng are soon after Razi and his sister, Shifa, too. And so begins an exhilarating adventure in the shadow of the biggest sea monster of them all.