After a shockingly brutal and unprovoked, broad daylight mass assault by knife (including the murder of at least two young women), at a a beautiful, idyllic Japanese resort, a film crew sets out to document the events surrounding the case, eventually coming to focus on the weird, seemingly supernatural events in the lives of the victims and assailant, both before and after the incident. As events progress, the documentary comes to revolve around the psychological impact of the attack on a chronically unemployed, and somewhat odd and pathetic man in his early 30s (upon whom the killer carved a series of petroglyph-derived symbols, during the initial attack, telling him it was "your turn next"), and the pattern of paranormal activity with seems to follow him about.
Eventually, the man decides that the initial attack was an act of God, as well as a ceremony intended to both honor God, and open a portal to another dimension. He believes the attacker from the opening scene now resides in this other dimension, as he was seen almost immediately jumping off a nearby cliff, but his body was mysteriously never found. After a series of encounters with huge, flying, apparently telepathic, and quite disturbing-looking, unEarthly entities of a possibly extraterrestrial or other dimensional nature, he comes to the conclusion that he has a God-given "duty" to perform a similarly violent "ceremony," which will enable him to make his journey into this other realm. After an encounter where the film director also witnesses the existence of these same beings, he reluctantly agrees to document the events. The ceremony is to take the form of a suicide bombing of a crowded Tokyo intersection. The bombing takes place, and 108 people are killed. Oddly, no trace of the body of the man wearing the suicide vest is ever located, while the director is convicted as an accomplice, and sentenced to 21 years in prison.
Upon his release from prison, now a man in his advanced middle age, he discovers both a video camera, and a 100-yen coin, both of which the man said he would send back to him from the other dimension, in the event he made a successful sojurn to it. The video camera includes a cassette showing the man's final moments on Earth, as well as his apparently successful transition into the other dimension. This dimension appears to be a realm of horrific lunacy and monstrous suffering, and is otherwise of a pseudo-Lovecraftian nature. The man pronounces it "Hell," and in terrified screams, he begs the director to help him, as other persons in obvious torment float in the space around him, and gigantic creatures with an appearance similar to jellyfish, seem to malevolently drift in their midst.