Riko and crew have encountered a mysterious cave raider squad in the depths' sixth layer! When they join them at their hideout, they find Srajo, the Sovereign of Mystery, awaiting them with a trial! Can they overcome her challenge and win her trust? Explore endless possibilities in this fantasy series that inspired the hit anime! 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!