Mai meets Naru while exchanging ghost stories with her friends, and learns her school principal has hired him to investigate an allegedly haunted school building. Mai later causes the injury of Naru's assistant and is forced to stand in as a temporary replacement. The principal also brings in several exorcists and mediums, and more help arrives in the form of a classmate of Mai's, who claims to have the ability to sense spirits.

Each member of the team proposes a different theory as to what is responsible for the odd occurrences. After collecting data overnight, Naru begins to doubt the presence of any spirits and instead theorises that land subsidence is the cause of all the ghostly activity. Mai's classmate, Kuroda, fiercely insists that a poltergeist is at work, and evidence appearing to support her idea soon arises.

Bou-san, Ayako, and Mai destroy the dolls, effectively removing the 'curse' on the school. Naru is sent to the hospital as a result of the manhole accident, where he makes a startling revelation regarding the past of someone at the school. He clears Kasai's name, but is forced to accuse someone close to her in the process. After the case, the team return to the SPR, where Naru successfully tests Mai for psychic abilities.

Masako requests Naru investigate a park where over six months, couples have had water dumped over them from thin air. The team, excluding Lin, split up at Masako's suggestion into pairs and they soon attract the spirit of a woman. Taking possession of Masako's body, the woman explains she died soon after being cheated on by her boyfriend. Mai convinces her to let go and move on to heaven, but not until they have forced the cheating partner to acknowledge the hurt he caused.

While Naru searches for Kenji's body, Lin is ordered to play with Kenji. Lin snaps shortly after and Kenji, still in Mai's body, races into the woods. After John and Bou-san find Kenji, Naru tells him his father is waiting for him in heaven and asks him where he is. Kenji shows him the place he'd hid and died in and releases Mai, who sees Kenji's tragic death in a dream.