Sadako's Grudge.

Mizuki, who has been assigned to a new high school along with her younger sister, has encountered numerous strange phenomena since their arrival. What could be the cause? The veteran teachers, who have worked there for years, begin to grow fearful. It seems that it may be related to an incident from 13 years ago. Can Mizuki and her group prevent the next murder before it happens? And what is the true objective of Mizuki’s sister, Anna?