Plot
At Ichogaoka School, on the day before summer vacation, a group of children accidentally break a small statue. When the school day ends, Mika, a second-grader, encounters a bouncing football while retrieving her paint set. She follows the ball into an abandoned wing of the school, where, in the upstairs bathrooms, she is lifted into the air by an unseen force. Elsewhere, Mika's mother asks Mika's older sister, Aki, to bring her home.
Fifth-graders Kensuke and Shota sneak into the abandoned wing of the school. Aki arrives, looking for Mika. She asks fourth-grader Hitoshi, who is drawing a magic circle on the ground in chalk, if he has seen Mika. She notices that the door to the abandoned wing is unlocked, and walks inside, where she meets up with Kensuke and Shota. Hitoshi soon follows and finds that the doors have locked behind him. Hitoshi's brother Kazuo, who has been absent from school for almost the entire term due to his belief that evil spirits haunt the premises, senses that Hitoshi is in danger.
In the abandoned wing, the children meet Kaori, a sixth-grader. The group witness a grinning spirit floating behind Shota, and flee in terror. Kazuo arrives at the abandoned wing with a schoolteacher named Shinichi Komukai, but the two are unable to see the children pounding on the windows of the now-locked building. Night falls, and Aki and Kaori are chased by a sandaled giant through the hallways of the wing. Aki hides in a closet and falls into a dark pit. Meanwhile, Shota, Kensuke and Hitoshi are attacked by an anatomical model, and meet a custodian named Kumahige.
Aki crosses paths with Shinichi and Kazuo, as well as Yumiko, Kensuke's mother and a former classmate of Shinichi. The four go to the abandoned wing, which unlocks itself. After Shinichi and Aki enter, the doors shut behind them, leaving Kazuo and Yumiko outside. Aki, Shota, Kensuke and Hitoshi see the grinning spirit behind Shinichi, and run. Hitoshi hides in a classroom containing clay models which transform into hands that envelop him. In a music classroom, Shota and Kaori witness an ensemble of ghostly string musicians. Outside, Kazuo sees Hitoshi in the rearview mirror of Yumiko's motorbike. Hitoshi tells Kazuo that a sacred object on school grounds, which kept evil spirits at bay, has been broken, but neither know what the object is.
Shinichi and the children encounter Kumahige, who sprouts arachnid-like appendages and chases them into an upside-down classroom. Desks fall from the ceiling, but Aki protects herself, Shinichi and Kaori using a diagram of a magic circle torn from a book. The paper transforms into a glowing butterfly, which leads them to the location of Hitoshi and Mika. Elsewhere in the wing, Shota and Kensuke encounter Kuchisake-onna, while outside, Kazuo begins drawing a large magic circle using a line marker, and Yumiko assembles a group of bikers to search the grounds for the sacred object.
After securing Mika, Shinichi and the children again face Kumahige. Hitoshi blinds Kumahige, who transforms into a large monster that lunges at Shota and Kensuke in a dumbwaiter. Shinichi and the children flee from the monster and find themselves at a door which leads to the dark pit that Aki fell down earlier. Shinichi jumps into the abyss with Mika in his arms, followed by Aki, Kensuke and Hitoshi. Shota discovers Kaori to be incorporeal, and falls into the pit without her. Outside, the bikers find the broken statue, which Kazuo places in the middle of the magic circle. It magically repairs itself, and both the statue and the circle begin glowing. A ball of light races through the abandoned wing of the school.
Shinichi, Mika, Aki, Shota, Kensuke and Hitoshi find themselves in the school swimming pool. They meet up with Kazuo and Yumiko. Yumiko tells them that, according to Kaori's father, Kaori was in the hospital and died some time prior to them meeting her. Some time later, Shota tells Kensuke that he wishes he had told Kaori he loved her. Shota, Kensuke, Kazuo, Hitoshi, Mika and Aki decide to go to Aki's house.
