Siren

An earthquake shakes the rural town of Hanuda, initially appearing routine. After the tremors, strange phenomena emerge: people infected with a mysterious affliction, violence erupts around the town, and all natural water sources are replaced by a red liquid. The town becomes effectively cut off from the outside world as the crisis deepens.

A Mana Religion ritual aims to call Datatsushi through the sacrifice of Miyako Kajiro. Kyoya Suda, an outsider, stumbles into the ceremony and unintentionally provides a distraction. Miyako resists death and flees, causing the ritual to fail and setting the disaster in motion.

The failed ritual triggers a dimensional rupture, pulling Hanuda into another world where space and time distort. Derelict buildings from the past reappear, replacing recent structures as the landscape shifts. The environment itself becomes a hazard as the crisis accelerates.

All natural water sources are replaced with the red water, turning Hanuda into an island surrounded by an endless red sea. The infected populace becomes shibito, displaying violent behavior, impaired cognition, eye bleeding, and rapid healing. The infection's spread marks a turning point in the crisis.

Across the town, the Siren—the call of Datatsushi—drives the infected to immerse themselves in the red water and recruit others. They begin constructing nests to house Datatsushi's corporeal form, signaling a cult-like effort to harvest the god's presence. The town's ecology now orbits around this ominous plan.

The Mana Religion's leaders pursued Datatsushi through human sacrifice, believing Miyako's psychic abilities would appease the deity. The failed ceremony exposes the town's isolationist faith and explains the catastrophe's roots. Survivors gain insight into why Hanuda fell into this nightmare.

Kyoya Suda, drawn by online ghost stories, begins investigating what happened in Hanuda. He uncovers clues linking Miyako's sacrifice to the ritual and the resulting disaster. His investigations bridge the town's secret history with the present horror.

The group of survivors navigates the broken town, fending off shibito attacks while seeking routes to safety. They confront the surreal landscape and exchange information to piece together what happened. Their efforts to escape unfold across shifting perspectives.

As the days unfold, Kyoya confronts the source of the nightmare and engages the shibito in a final stand. He slays Datatsushi at the end of the three days, halting the immediate threat. The victory comes with a cost, leaving Hanuda still trapped in a distorted present.

Harumi Yomoda escapes Hanuda and returns to the real world. She is the only known human in the town not infected by the red water, a solitary survivor of the apocalypse. Her escape marks the presumed end of the crisis for those who remain.

Visitors Shiro Miyata and Risa Onda persist in finding an exit, moving through the eerie landscape in hopeful pursuit of freedom. They join the broader effort to escape and uncover answers, facing threats and confusion along the way. Their fates remain open as the timeline threads continue to intertwine.

The infected press on with nest-building, and some shibito develop new traits such as insect-like wings. This mutation underlines the evolving threat as the town's ecosystem morphs under Datatsushi's influence. The survivors confront a finale where stopping the god's return remains the central goal.