Escha's recipe to purify the village's reservoir works, but the pollution continues and she travels upstream with Logy in search for the cause.

By suggestion of her friends, Escha attempts to make a copy of her artificial tail but despite being a profitable opportunity, she is more interested in doing so to learn more about her late mother, who created it for her.

Lucille Ernella, a specialist in medicine, arrives from central to work on the R&D division under Escha and Logy. Despite proving herself quite capable compared to her peers, Lucille gets herself in trouble when she attempts to perform her duties without asking for assistance, until Escha and the others come to her aid.

Escha is tasked to find a new way to improve the harvest on the local orchard and while looking for some ideas, she and her friends decide to hold a contest to look for recipes to make with the discarded apples while an eating contest is held at the local restaurant.

The members of the R&D division prepare for the arrival of an auditor to check on their work, when one of their members, the swordswoman Linca is spotted causing trouble around town and is put under suspicion, despite claiming innocence, until Escha and Logy learn from Marion the truth about her.

With their assignments done for a while, the R&D division is up for some well deserved vacation, when Wilbell appears and convinces them to accompany her on a hot springs trip near a volcano, unaware of her true intentions.

Escha always dreamed of reaching the unexplored ruins that float near her city. When their friend Threia decides to issue a request to look for a mean to reach the ruins, Escha cheers up, just to have her dreams crushed when they are ordered by the higher ups to make preparations for another team to attempt it. However, Escha's friends decide to not give up and make plans to form their own exploration party instead.

While looking for key components to complete an airship, Escha learns about Logy's dreams, but that a tragic accident made him abandon them.

The group meets an enigmatic girl named Flameu who drives them away from the ruins. After hearing about her story, Escha decides to return to the ruins in order to help her.

Escha and her friends return to the ruins to face Flameu. They attempt to free her from what binds her to the ruins, but in the end, it is up to Flameu.