Mentioned Characters: Yukari, Kosuzu

Kosuzu Motoori is a human girl who lives at Suzunaan, a book rental shop in the Human Village. She serves on the library committee at Hakurei Shrine Academy, spending her days reading through the collection and carefully shelving each book when she's done. Lately, she'd taken an interest in another version of herself who came from a parallel world―a distant, hard-to-approach Kosuzu who seemed to keep everyone at arm's length. Concerned, Kosuzu had been thinking about reaching out... and maybe even inviting her to join the library committee.

A Kosuzu Motoori from a parallel world had made her way to a Gensokyo, where students endlessly cycle through enrollment and graduation. Armed with the power of demon books such as the Privately Published Night Parade Scroll: Final Chapter Addendum, she was determined to "fix" Gensokyo. At first, she relied on extreme methods, even resorting to destroying things in the academy. But thanks to the support from her friends at school, she chose a different path: using that same power to return the library's books to their rightful places.

In this Gensokyo, where students endlessly cycle through enrollment and graduation, Hakurei Shrine Academy sees its fair share of problematic transfer students each spring―almost like a yearly tradition. Kosuzu Motoori, who arrived from a parallel world, was once one of them. With her long red hair whipping around like it had a mind of its own, she would roam the halls, attacking those she felt were exploiting youkai. But then, one day, something about her changed. The most obvious signs were her clothes and hair. When she showed up at school, her once-unruly hair was neatly tied back, and more surprisingly still, she was wearing what looked like the academy's official uniform. What could have possibly caused such a transformation? The first one brave enough to ask was none other than the Kosuzu of this world.

The ABCs of Friendship "Huh?! Kosuzu, your hair's tied back!" "...And? You have a problem with that?" "N-No, not at all! I just think it looks super cute! Look, we match!" "I didn't have any other reference, so I copied you." The transfer student Kosuzu looked away as she answered. Apparently, she'd based her look on this world's Kosuzu. "It kinda feels like I have a sister now." "...Don't get the wrong idea. This is all part of fixing Gensokyo." "What do you mean?" "The relationship between humans and youkai here isn't how it should be. So I've decided to fix this flawed Gensokyo, one step at a time. First, my look... Next, the library system." "Um... What?" "Kosuzu. Take me to the library."

"Wow, Kosuzu, that's amazing!" "I'm just pulling out books that are out of order." The transfer student Kosuzu replied without so much as a smile. What she said was true, but not the whole truth. "...Hey, Kosuzu? It looks like there are demon books on the shelves here. Do you know why?" "Um... I'm not really sure why, but when no one's around, I read them. They're really... interesting." "I see..." As if entrusted with a secret, she nodded, then quietly checked the loan cards for the demon books. Every single one had the same name written on it―Yukari Yakumo. "I'm going out for a bit. Looks like someone hasn't returned their books." "O-OK! Be careful!" She felt like Miss Yukari was plotting something again. Determined to find out what, Kosuzu left the library.