The story begins with the eldest sister Iina appraising the red library uniform designated for her baby sister Kokoro who is starting out as a librarian at Kokoro Library. After the middle sister Aruto scolds Kokoro to always be punctual and Iina photographs the occasion, Iina and Aruto's divergent perspective of professional conduct gives way to the three sisters opening the library only to encounter little action until the lunch break where Kokoro is advised to be patient -- very sage counsel when her first customer Kaede Hoshino arrives searching for an out-of-print book that Kokoro…