这是除灵师京极堂开旧书店之前的故事——
故事发生在昭和 23 年，东京。
刚升入新制高中的二年级学生日下部栞奈，遇见了新任国语老师中禅寺秋彦。
在栞奈的周围，接连不断地发生各种不可思议的奇妙事件。
今天也一样，寻求帮助的栞奈，推开了外表冷傲的中禅寺老师所在的图书室的门——。

In 1948 Tokyo, just right after the war, Kanna Kusakabe had just become a second-year at a high school when she meets the new language teacher, Akihiko Chuzenji. Mysterious supernatural things keep happening around Kanna. Once again today, Kanna is going to open the doors to the library prep room to seek help from the surly Chuzenji-sensei who is waiting inside.

In a world where Skill Fruits grant powers, aspiring adventurer Light is stuck with the useless «Fruitmaster» skill. Eating another one results in death, so no do-overs. Meanwhile, his childhood friend Rena quickly rises to S Rank. But when Light accidentally eats a second Skill Fruit, he survives and discovers his true power: He can consume unlimited Skill Fruits and gain their abilities!

In a fantasy world where eating Skill Fruits grants magical abilities, Light Underwood dreams of being a great adventurer. But the first fruit he eats gives him the “Fruitmaster” skill — which only helps him grow fruits, and is virtually useless in combat. Meanwhile, his childhood friend Lena eats a Sword Saint fruit and quickly becomes an S‑rank adventurer. Light resigns himself to a quiet, non‑glamorous life: farming fruit and training with a sword. But then everything changes — one day, he accidentally eats a second Skill Fruit, which should kill anyone who already has a skill. To his shock, he survives. He discovers that his “useless” Fruitmaster skill actually has a hidden power: he can eat unlimited Skill Fruits without dying, and each time he does, he gains a new skill.