Riko wants to follow her missing mother, Lyza the Annihilator, into the farthest reaches of the Abyss. But Lyza is a legendary White Whistle, while Riko holds only the novice rank of Red Whistle and is permitted to explore no farther than the chasm’s uppermost layer. An unexpected encounter with a robot who looks like a young boy gives her a new reason to venture deeper.
She names him Reg, but he remembers nothing from before their meeting. Convinced that the technology behind his creation originated far below, Riko sets out with him to recover his memories and reach the bottom. Their destination has long drawn explorers known as Divers, who search its depths for answers among strange creatures and ancient relics. Neither Riko nor Reg yet understands the harsh reality awaiting them within the Abyss.
