Within the depths of the Abyss, a girl named Riko stumbles upon a robot who looks like a young boy. Riko and her new friend descend into uncharted territory to unlock its mysteries, but what lies in wait for them in the darkness?

Set directly after the events of Made in Abyss: Dawn of the Deep Soul, the fifth installment of Made in Abyss covers the adventure of Reg, Riko and Nanachi in the Sixth Layer, The Capital of the Unreturned.