Taichi just entered high school and starts living at his cousin's house where four sisters live, Otoha, Kaguya, Momone, and Nora. They are all teachers at his school. On his first day there, he has a party with them and goes to bed early. When Taichi wakes up at midnight, he is surprised to see Kaguya, the second oldest sister, giving him blowjob! He can't do nothing except pretending to be asleep. On the next day, there is no sign of the event. Was it just a dream? Like this, their erotic school life starts...