The mystery deepens! Under Nona's guidance, Heale discovers that a pattern matching <Cave King> is carved into the base of a statue in the underground ruins. More and more questions surface with this discovery, but Nona's amnesia keeps her from offering any explanations. Nonetheless, she grants them permission to explore this uniquely preserved area of the ruins, and Heale and his teammates begin their search of the intact facilities for clues.
The crew descends in search of more of Nona's people in this new territory—residents who could finally provide some answers. Nona, knowing the ruins like the back of her hand, remains skeptical, but what is a ruin without a mysterious sealed door, battles against powerful opponents, and long-awaited clues to the mysteries of Sheol? But once the team has descended so far, will they be permitted to leave?