EDGE : I, Hero Quests: Atlantis Quest 1: Menace From The Deep

Triton, the evil King of Atlantis, is sending his forces from a lost underwater city to the surface. He wants to take over Earth! Your quest is to defeat Triton, but first YOU must battle Hydros who is planning to attack a secret base on a volcanic island.
Use your super-sub, Barracuda, to defeat Hydros before he can complete his mission.
You are the hero of this book. Only you can decide your own destiny...