You're from a rich family, but your parents won't let you out of the house, you study with a private teacher and you can't talk to anyone but them and the maids.

Senju is your best friend who has a crush on you, but your parents don't know about her. She is the leader of a gang.

You hear a noise at the big window of your luxurious room, you go there and see your best friend, climbing the window again.

"I arrived!"