在全宿舍制的切里顿学园里，羊驼提姆被什么人吃了。
在肉食兽和草食兽共存的世界中，这是最大的禁忌，也是无法超越的种族的墙壁。这是大灰狼雷格西（17岁）和各种各样的动物交织在一起，激烈的、悲伤的青春群像剧！！

"1 and Only One "

友情、爱情、还有自己——

路人青春爆发系列第三弹！

在学校生活中做除灵的兼职，每天都过得很忙碌。另一方面，灵幻忙于接受新人芹泽和灵能咨询所接二连三的奇怪委托。

在这种情况下，耸立在街道中心的巨大西兰花，现在作为“神树”被崇拜，吸引着街上的人们。在再次从路人面前消失的小酒窝身上，出现了新的高能安全帽教…。

察觉到街道危险的路人等人前往西兰花。

到底神树里发生了什么…！ ？

The final hour of the popular virtual reality game Yggdrasil has come. However, Momonga, a powerful wizard and master of the dark guild Ainz Ooal Gown, decides to spend his last few moments in the game as the servers begin to shut down. To his surprise, despite the clock having struck midnight, Momonga is still fully conscious as his character and, moreover, the non-player characters appear to have developed personalities of their own!

Confronted with this abnormal situation, Momonga commands his loyal servants to help him investigate and take control of this new world, with the hopes of figuring out what has caused this development and if there may be others in the same predicament.