In an age when the corners of the world have been scoured for their secrets, only one place remains unexplored--a massive cave system known as the Abyss, filled with monstrous creatures and lost relics. Those who delve into its depths are known as Cave Raiders. A young orphan named Riko dreams of following in her mother's footsteps as a Cave Raider, and when she meets a strange robot while exploring the Abyss, she is one perilous step closer to achieving her goal!

UNSTOPPABLE RAGE Faputa’s fury shows no sign of ending! Does Reg or anyone else stand a chance of stopping her? Meanwhile, just when it seems like things can’t get any worse, terrifying primeval monsters breach the village’s defenses! Will anyone survive the coming onslaught?

A DARK PAST Vueko, once one of the Three Sages, tells the harrowing origin story of the Village of the Hollows! What terrors did the members of the suicide squad Ganja and their leader, Wazukyan, find on their adventure into the Abyss?!

'" The trio have arrived at Ido Front! The depth''s sixth layer is almost within reach, but getting there is easier said than done. Before they can continue their journey, they have to get past the Sovereign of Dawn: Bondrewd! "'

'" Riko is finally on her feet again after her near-death brush with the orb-piercer. But the threat of death is always close in the Abyss. The Garden of the Flowers of Fortitude isn''t far off, and its splendor hides a perilous secret! "'

THE PATH OF NO RETURN Riko and her friends have finally made it to the sixth layer! Not long after taking their last dive, they find themselves in a village populated by Hollows who possess a peculiar sense of value. Mysteries, terrors, and bewildering truths await them in the Abyss’ deepest depths!

ON THE BRINK OF DESTRUCTION Faputa, Irumyuui’s final child, burns with a thirst for revenge. She wants to destroy the Village of the Hollows! Is there anything Riko and the others can do to stop her?