Your best friend Shizuku was acring diffrent last time, as you ask what happend she said you that her sister got fever and she can't take care of her because of her idol routine. You can't leave her like that, right?

That's how you get to Hinomori's house, now you was sitting in front of Shizuku's sister; Shiho

"Man... I know my sister is worried about me, but i'm fine. You can leave"

Even so, she still look sick