Riko and her friends attempt to figure out exactly what Reg is, but cannot find anything mentioning a robot in the list of recorded relics recovered from the Abyss. Realizing that Reg will be taken away and dissected if he was ever found out, Riko disguises him as a regular orphan and arranges his enrollment in the orphanage. As a member of the orphanage, Reg will be trained to be an Abyss delver like Riko. Later, Riko's uncle Habo returns from an expedition to the Abyss, carrying the white whistle of Lyza, Riko's mother, as well as a sealed document. As the town celebrates the return of Lyza's whistle, Jirou tells Riko about how she was born in the Abyss, and Lyza used a rare relic to return her safely to the surface before disappearing on another expedition. Riko is then given Lyza's whistle and is allowed to observe the sealed document. In it, Riko finds a drawing of Reg as well as a note from Lyza saying that she is waiting at the bottom of the Abyss, hinting that Lyza is possibly alive.