The City of the Great Pit
While exploring the Abyss, Riko comes across something she has never seen before. How does this new discovery impact her?
Episode 1•23m
Resurrection Festival
Riko and Reg find out more about their past but the question still remains, who or what exactly is Reg?
Episode 2•23m
Departure
Reg goes on his first cave raid! Meanwhile, Riko makes preparations to go into the abyss to find her mother.
Episode 3•23m
The Edge of the Abyss
Riko and Reg start their adventure into the Abyss, while there they run into an unexpected familiar face.
Episode 4•23m
Incinerator
Riko and Reg descend into the Forest of Temptation. What new dangers will they find laying in wait for them there?
Episode 5•23m
Seeker Camp
Reg and Riko make it to the Seeker Camp where they meet Ozen the Immovable, the person who saved Riko all those years ago. But there is more to Ozen than meets the eye.
Episode 6•23m
The Unmovable Sovereign
Ozen reveals more about the Abyss as well as the truth behind Riko's origins. What will happen when Ozen shows her true colors?
Episode 7•23m
Survival Training
Ozen tasks Riko and Reg to survive alone outside the Seeker Camp. Do they come out alive and unscathed? Or does the Abyss have a dirty trick up its sleeve?
Episode 8•23m
The Great Fault
Reg and Riko continue their descent after they leave Ozen's Seeker Camp. Riko's mettle is tested as Reg passes out and she has to fend for herself.
Episode 9•23m
Poison and the Curse
Reg and Riko run into trouble deep in the fourth layer where they meet an interesting creature, but are they friend or foe?
Episode 10•23m
Nanachi
Nanachi sends Reg on a mission to find certain items that could possibly save Riko. Meanwhile, Nanachi reveals a little more about themself.
Episode 11•23m
The True Nature of the Curse
Nanachi shows Reg the truth about the Abyss. Meanwhile, Riko is still recovering from her injuries when she has a strange dream.
Episode 12•23m
The Challengers
Nanachi and Mitty's past is revealed. How did they become what they are and who is responsible for it? Meanwhile, Riko is on the mend after her injuries.
Episode 13•47m
The "Abyss" is the last unexplored place in the world. Strange and wonderful creatures roam within, and it is full of precious relics that present humans can't recreate. Those that dare to explore the depths are known as "Cave Raiders." An orphan girl named Riko lives on the rim. Her dream is to become a Cave Raider like her mother and solve the mysteries of the cave system. One day, Riko starts exploring the caves and discovers a robot who resembles a human boy. (Source: Anime News Network, edited) Note: The last episode aired with a runtime of ~48 minutes as opposed to the standard 24 minute long episode.
