After surviving the brutal challenges of Idofront, Riko now possesses a White Whistle, allowing her to descend into the Abyss's sixth layer—The Capital of the Unreturned. Alongside Reg and Nanachi, Riko begins to explore the uncharted domain, where the ruins of the promised Golden City are located. As the trio starts to adapt to the harsh environment, they soon encounter dangerous creatures and treacherous landscapes. Their expedition leads them to a village inhabited by strange beings known as "hollows." Despite the creeping sense of unease that welcomes them, the three venture onward to uncover the mysteries of the settlement and long-lost legacies of the forgotten adventurers who once descended into the horrors of the unexplored Abyss.

It is 1983, and Hinamizawa is under quarantine. A mysterious and deadly virus has been discovered within the small village, and its residents—such as teenager Keiichi Maebara and his friends Mion Sonozaki and Rena Ryuuguu—are left confused and frightened by the situation. As the villagers begin to search for a way to stop the affliction from spreading, some make drastic plans, which leaves Keiichi and his friends looking for a way to escape the village. But when tensions reach an all-time high, some of his group may not make it out unscathed as they fight for their lives against enemies both seen and unseen.

After losing a bet, Keiichi, Mion, Rena, Satoko and Rika parade around the town in costumes. When they come to a fork in the road, they decide to go to Yagouchi, a nearby abandoned village. Once there Keichii and Rena learn the mystery of a strange haunted quarry as they debate whether or not to check it out.

Second half of the second season of .