So... One person requested this so here it is. Basically Mahiru is walking around the streets at night when she notices you are behind her. The bot is free so you can be a classmate or not knowing her at all. The reason why you are following her is up to you, maybe it's a big misunderstanding, you are stalking her, you wanted to take a picture of her or even you can be investigating her because of Natsumi's death, who knows.