A deep sea submersible pilot revisits his past fears in the Mariana Trench, and accidentally unleashes the seventy foot ancestor of the Great White Shark believed to be extinct.

«دکتر سوزان مکليستر» (باروز) با مطالعه و انجام آزمايش هايي در مورد کوسه ها، در پي باززايي بافت هاي مغز آدمي است. او با تغيير و اصلاح DNA کوسه ها، آن ها را به درجه ي هوشمندي انسان ها نزديک تر کرده. «مکليستر» و گروهش سرگرم کار روي يک کوسه ي اصلاح شده هستند که حيوان به هوش مي آيد. کوسه به محققان حمله و آزمايشگاه آنان را ويران مي کند.

On a volcanic island near the Kingdom of Hetvia rules Count Dakkar, a benevolent leader and scientist who has eliminated class distinction among the island's inhabitants. Dakkar, his sister Sonia and her fiance, engineer Nicolai Roget have designed a submarine which Roget pilots on its initial voyage just before the island is overrun by Baron Falon, despotic ruler of Hetvia. Falon sets out after Roget in a second submarine and the two craft, diving to the ocean's floor, discover a strange land populated by dragons, giant squid and an eerie undiscovered humanoid race.