The Orchard of Stray Sheep (2016)

Happiness is an obligation. But then, what gives one the right to be happy? A small, garden-like Academy stands alone on a secluded island. Ichirou Yamada has been transferred there to work as a teacher. He is put in charge of Casserole, a beautiful, young girl who entered the school at the same time. However, things are not what they seem at this "academy"...