Під час дослідження Абіса, Ріко натрапляє на те, чого вона раніше ніколи не бачила. Як ця знахідка вплине на її життя?

Ріко разом з друзями з притулку намагаються дослідити робота-хлопчика, той приходить до тями, але нічого не пом’ятає. Від Ріко він отримує ім’я Рег. Діти вирішують приховати, що він робот та Рег прикидається сиротою. Ріко дізнається, що її давно зникла мати Лайза можливо ще жива.

Reg goes on his first cave raid! Meanwhile, Riko makes preparations to go into the abyss to find her mother.

Riko and Reg start their adventure into the Abyss, while there they run into an unexpected familiar face.

Riko and Reg descend into the Forest of Temptation. What new dangers will they find laying in wait for them there?

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.

Ozen reveals more about the Abyss as well as the truth behind Riko's origins. What will happen when Ozen shows her true colors?

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?

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.

Reg and Riko run into trouble deep in the fourth layer where they meet an interesting creature, but are they friend or foe?

Nanachi sends Reg on a mission to find certain items that could possibly save Riko. Meanwhile, Nanachi reveals a little more about themself.

Nanachi shows Reg the truth about the Abyss. Meanwhile, Riko is still recovering from her injuries when she has a strange dream.

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.

An old man speaks of a golden city that lies within a devouring abyss somewhere in uncharted waters. One explorer may be the key to finding both.

Riko, Reg and Nanachi take their first steps into the sixth layer. Both wonders and dangers await the trio, but they are unaware they are being watched.

Riko couldn’t have known the consequences of her words, but she sealed the villager’s fate as soon as she acknowledged Meinya was priceless. The Balancing has begun…

Faputa and Reg once knew each other, but Reg cannot remember her at all now. Meanwhile, Nanachi is stunned by news so unexpected that it should be impossible to believe.

Some say there’s a secret hidden deep within the dark cave at the edge of the village. Villagers don’t investigate and stay far away, but Riko isn’t a villager.

The villagers must lure abyssal fauna into the village to hunt them. But when one creature proves too much to handle, Riko needs to help the villagers defend their home.

What happened to the expedition? The truth is far more tragic and horrifying than anyone could have imagined.

They had their reasons for descending into that infernal pit. They found damnation and salvation in equal measure.

Faputa can help Reg save Nanachi, but everything has a price. In exchange, Reg must help her enter the village.

The reckoning comes, but Reg is too kind and foolish to be a bystander.

The village’s membrane has been breached, and through the gap floods chaos itself. But as attackers enter from without, aid comes from within.

In the end, everything comes full circle.