Kaii-bu: M-ken Y-shi no Kaigenshou ni Tsuite

When transfer student Sakura Sakuraba arrives in Yuuyamichou, she discovers a place steeped in bizarre, ancient customs. The children there all have strange names and are bound by a curse that prevents them from leaving the city until they graduate high school. Caught in an escalating nightmare, Sakura must navigate curses, summonings, and betrayals. To break the curse and free the children, Sakura teams up with Uzu Andou, the mysterious president of the Paranormal Club. Their strange "club activities" are about to begin!

(Source: Kadokawa, translated)