Another by Yukito Ayatsuji

Teenage Koichi Sakakibara finds himself falling ill and moves back to his mother's hometown of Yomiyama. He attends Yomiyama Middle School and encounters the odd Mei Misaki. As Koichi gets to know Mei, he and the rest of the class find themselves caught up in a strange phenomenon that plagues Class 3-3 every year... A phenomenon in which the students or their families are subjected to gruesome and senseless deaths.