A school frozen in time, volume 2 (Vertical Comics)

A regular school day has turned into a chilling horror as Hiroshi, Mizuki, and their friends find themselves confined within the frigid walls of Seinan Gakuin. No one can seem to remember who took their own life at the school festival, but whoever it was is keeping them captive. And to make matters worse, the eight trapped classmates become seven when Mitsuru suddenly disappears with only a trail of blood in his place. Now they have even more reason to solve the mystery of their bizarre circumstances -- because if they don't, the only thing they may be leaving is this mortal coil...