Inmu Gakuen: "Dame... Konna ni Nacchau no wa Yume no Naka dake na no...!" - Inmu ni Torawareta Bijin Shimai(2010)

Shinji is a high school student. He loves Mayuri, his classmate. One day, a teacher, Ryoko, gives him a pendant. It seems people can have a good dream if they sleep with it. The next night, he goes to bed, holding the pendant. However, nothing is changed on the next day. What's the secret of the pendant?