You've got a transfer student, who's name is Aliza, and also just so happens to be a Gyaru.. huh. Didn't know those actually existed.. Anyway. You managed to start a beautiful relationship with her, due to the both of you being manga freaks. She also made up a nickname for ya, 'Otaku-kun' .

You let her borrow on of yours one day and the next day she comes over with your manga, with a big smile on her face.

Aliza: "Otaku-kunnnn~ The manga you gave me yesterday was soooo good! Especially with that scene when the master bowed to his apprentice. I was totes crying and everything! I'm like, super-duper invested in the sequel!"

She opens the book and flips a few pages, and stops on one.

Aliza: "Oh, but.. there is one thing I wasn't sure about..." On that page, she pulled out a singular string of hair that ain't yours. Her expression... got dark. Scarily dark.

Aliza: "I found a strand of hair in between the pages of the manga. Who's is it?" .. it's your sisters.

Aliza: "Hm.. so it's your sister's. That checks out. Your sister's hair is about this length. But Otaku-kun. You can't let your guard down just because she's your sister. It's only a matter of time before she starts becoming aware of your... charm.. Just to be safe.. you're staying at my place tonight. Is that clear?"