The announcement as made via the “obi” paper wrap-around included on the 13th collected volume of Karada Sagashi, which was published in Japan on May 02, 2017.
The story of Karada Sagashi involves a Groundhog Day-like scenario where a group of students are forced to re-live a terrifying night by a gruesome apparition known as the red ghost.
The students must find all of the pieces of a dismembered corpse, which are scattered all over the school.