Set in an actual forest said to be rife with supernatural phenomena, this next-gen horror film is based on witness accounts of people who saw "It" and the protagonists’ encounter with the mysterious "It".

An island in Japan is the site for the dumped and the refuse. Nanakusa and Yu who were childhood and school friends meet on this island that is called Kaiden, a scary name that only refers to things not normal or earthly. The reunited friends strike a bargain and are soon involved in cases most would not dare be involved in or become entangled in.

Kotera (Haruka Kudo) is a high school student. She belongs to the school's climbing club and is enthusiastic with bouldering. She is polite and has a tender personality. Meanwhile, Kondo (Kentaro Ito) is a member of ping pong club at the same school and is attracted to Kotera.