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.
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.