Ao Oni translates to Blue Demon. Story: 3 boys and 1 girl enter a mansion which is rumored to have a monster in it.
Hiroshi, the protagonist, denies monsters existing and exclaims that it is "scientifically impossible". Hiroshi goes to explore a sound and finds out that it was just a plate shattered on the ground. Hiroshi returns to the room to see his friends missing. He sets out exploring to find them.