A story of a rat family who have to leave their home because humans start a construction site. Now the rats are searching for a place to stay.

As New Year’s Eve draws closer, preparations for a holiday party are underway in Petersburg. In anticipation of the event, Eila Ilmatar Juutilainen of the 501st Joint Fighter Wing is determined to take Sanya V. Litvyak on a leisurely walk around the city. However, despite Eila's best intentions, she gets interrupted every time she gets a chance to ask Sanya out, ruining the moment and separating the girls. To make things worse, a Neuroi is approaching the base, threatening both the squadmates and the celebration in Petersburg.

High school student Aoi Aioi lives with her elder sister, Akane, after a tragic accident took their parents away 13 years ago. Because Akane has since been taking care of her single-handedly, Aoi wants to move to Tokyo after her graduation to relieve her sister's burden and pursue a musical career, inspired by Akane's ex-boyfriend Shinnosuke "Shinno" Kanamuro. Shinno was part of a band until he left for Tokyo to become a professional guitarist after the sisters' parents passed away, and he was never to be seen again.

One afternoon, while Aoi practices her bass in a guest house, she gets startled by the 18-year-old version of Shinno from 13 years ago! As if by coincidence, the current 31-year-old Shinno also returns to the town, but he has changed drastically. There are now two Shinno's in existence, but why is the Shinno from the past present?

Sora no Aosa wo Shiru Hito yo revolves around these four individuals as they confront their inner feelings toward each other and make decisions that will affect their lives from here on out.

[Written by MAL Rewrite]

A recap episode of the original series made to connect Yuuki Yuuna wa Yuusha de Aru: Washio Sumi no Shou to the sequel series Yuuki Yuuna wa Yuusha de Aru: Yuusha no Shou.