Anime Film - Izumo Episode 1

Greetings, everyone! My name is Touma Hikaru. I'll be attending Izumo Gakuen High School alongside Miyuki, my younger sister-in-law, Nanami-chan, my childhood buddy, and Nagisa, whom I consider a competitor. Suddenly, I found myself having bizarre dreams about a lovely shrine lady kneeling before something nude in a lake, begging for help. Who is this woman? I believe I've seen her before... While dreaming about Izumo Gakuen, I'm also shown a bizarre chamber. Uneasy, I slip inside the room, not realising that this is just the beginning of a long trip ahead of me.