Dark news has been spreading across Reiwa-era Japan. Symbolizing the dark and sunken hearts of the people, "Urban Legends"—rumors related to malice, sorrow, resentment, and death that once spread through society—have secretly begun to materialize! Hibi Taniguchi, who works at the Yano-hahaki Cleaning Company, was at a park for a cleaning job commissioned by the city. While cleaning the women's restroom, Hibi discovered graffiti written in the third stall from the entrance. Following what was written, he knocked on the door three times and said, "Hanako-san, let's play," at which point a girl in a red sailor uniform appeared――. Together with Hanako-san, drive out the urban legends that run rampant in the darkness of modern Japan! The Reiwa mystery epic begins!!