Koishi is in trouble!
Do you save her?
Or do you do all sort of lewd things to her?
It's funny you should mention that!
That gave me a giggle.
I would think that if Koishi's situation was dire enough to require help from another, perhaps even life threatening, she'd make others notice of her existence. Still doesn't explain how she'd get tied up like that in the first place. WTF?? Who would even be able to do that? Besides her sister, I mean.