The story of "Deep Lake Behemoth" takes place in Canada decades after the end of World War II. In order to survey the oil resources under the Arctic ice, an American oil company developed a high-tech equipment worth 5 billion US dollars. But the equipment mysteriously disappeared in the vast Canadian deepwater lake area and disappeared in a vast lake area. In order to find the lost equipment as soon as possible before the competitors find it, Sean, an experienced diving engineer, had to interrupt his vacation and come to the lake area with his son and a full set of search equipment. They thought it would be a relaxing diving trip like a vacation, but they didn't expect that what was waiting for them, in addition to the legendary big water monster, was a thrilling and wonderful fantasy journey...