In an unused classroom in an old school building, there's a room with a curtain covering it, prohibiting entry for those under 18? A group of girls hear such a rumor. Feeling like a school ghost story, they set off on an adventure to find out the truth! They discover a classroom with a curtain covering it! They timidly peek inside... and find themselves in a lewd world beyond their imagination! And once they step inside the classroom, they find themselves drawn into that naughty world, and have sex...