The megamouth shark is a recently discovered species of deep-sea shark. Only 50 specimens have ever been sighted. Many of these sightings took place in Suruga Bay and Sagami Bay, beneath the shadows of Mt. Fuji. These waters have long been known to hold a treasure trove of deepwater sharks. Prehistoric “living fossil” sharks such as bluntnose sixgill sharks, goblin sharks and frilled sharks also lurk in the bay. Four years of studying and filming aim to shed light on the mysterious world of deep-sea sharks. As part of the investigation, a sperm whale carcass was placed at the bottom of the bay to attract these sharks. They were then studied and observed from submersible vessels. At last, the previously unknown behavior of deep-sea sharks has been captured on film.