In the perilous Black Ocean lurks Narga the Sea Monster. As well as preying on the rebels and fighting evil wizard Malvel, Narga is holding one of the good Beasts of Avantia captive. Can Tom set the good Beast free, or will it remain trapped in the Dark Realm for ever?<p>"Tom," Elenna said, "Do you think-"<p>She broke off as a dark shadow loomed over them, cutting off the red light of Gorgonia's setting sun.<p>Tom whirled round. Rising out of the sea were six enormous snake heads.<p>"Narga!" Elenna gasped.<p>