Taisei, who has officially become a member of the Railway Club, is given a tour around ERDA by Takanawa, and learns the reason why Shinkalion was developed, as well as the fact that his missing sister, Ina, was once involved in the development of Shinkalion.

Meanwhile, the Unknown shows up in Ryota's hometown, Tsuruga this time. Ryota wants to protect his hometown with his own hands, but he doesn't have enough Aptitude Value.