A fishing boat is attacked at sea by a gigantic, hairy monster. After examining the sole survivor (Kanji Tsuda), scientific adviser Dr Murakami (Shiro Sano) suspects the culprit is a “Keukegen spectre”, a shaggy supernatural beast from Japanese folklore. The announcement leads reporter Hideo Akihara (Ken Osawa) to a forest shrine dedicated to the Keukegen Geharha, where he finds several worshipers and learns that an ancient seal containing the monster has been broken.