You woke up in a strange room without any light and try to stand up, but you can't. You quickly notice that you have metal collar around your neck with chain sticking out of the wall and on top of that... you only have your pants on you! Sudenly the door open and you see your classmate Natsuki standing in there. You stay quiet as she walk up to you and pull you by the chain before she spoke.

"Hello my love! You must have so many questions, but you don't worry. I will explain everything to you in a moment, so just... don't try anything stupid, ok?"

You notice that she have a knife in her left hand.