Oshikiri has been hearing footsteps on the upstairs floor of his home. His cousin, Takayuki, believes that an intruder is hiding there; but can't find anyone. Oshikiri claims to hate the police, and refuses to get them involved.
Oshikiri is reading in the school library when another student, Kamiyama, claims that he senses the presence of people from another dimension; such as the Bermuda Triangle. The book Oshikiri's reading has a chapter about the Bermuda Triangle. Kamiyama asks to borrow it, and invites Oshikiri to join in the discussion. Oshikiri begins spending time with Kamiyama and his friends, Watanabe and Koizumi. Their conversations are usually about the supernatural. When Oshikiri tells them about the footsteps in his house, all of the others are very excited. They invite themselves over to the house.
Kamiyama, Watanabe and Koizumi all agree there is something strange about the house. They wait, but don't hear any footsteps. Oshikiri suggests they go home and come back another time, but Kamiyama says he's feeling the signs of another dimension more strongly than ever. They believe that an entrance to this dimension must be somewhere in the house. The group returns the following day, and all agree to stay over late until they can hear the footsteps. They discuss the alternate dimension which, they believe, looks very much like this world but with some differences.
Everyone hears the footsteps of someone walking across the upstairs floor, then down the stairs and outside. They look out of the window to see an alternate Oshikiri, who has murdered someone and is burying the corpse in the garden. Oshikiri yells at the intruder, who laughs wildly before disappearing. Oshikiri's friends cannot find an entrance to the alternate dimension, and think that perhaps the alternate Oshikiri is not limited by this and can travel anywhere.
When they go outside and look at the body, they see it is the corpse of an alternate Kamiyama. When they dig further in the ground, they find that an alternate Watanabe and Koizumi are buried there as well. The real Kamiyama, Watanabe and Koizumi come to the conclusion that alternate Oshikiri is a serial killer. They do not blame Oshikiri for this, and assist him in giving the bodies a proper burial.
Subsequently, Oshikiri continues to hear the footsteps. He feels that they seem more menacing now.