Storyline
Four years have passed since the devastating UNKNOWN-LV4 outbreak that caused a massive loss of life in the Tohoku region. Thanks to strict quarantine measures and the development of the Anti-UNKNOWN-LV4 vaccine, the disaster has gradually faded from public memory.
Wataru Ayase lives in Tokyo and has become accustomed to everyday life in the busy capital. Although he sometimes feels out of place in the constantly changing city, he continues to enjoy an ordinary life with the people around him.
Everything changes when Wataru encounters a mysterious girl with striking red eyes. At first, the encounter seems insignificant, but it soon becomes connected to a new outbreak of the UNKNOWN virus.
The infection begins spreading through Tokyo, causing people to behave violently and irrationally. As the situation deteriorates, the city's normal order rapidly collapses and Wataru finds himself trapped in an increasingly dangerous environment.
Wataru must navigate the chaos while trying to protect the people who matter to him. As the outbreak spreads, different characters become involved in the unfolding disaster, and their relationships and decisions affect the events that follow.
With Tokyo descending into chaos, Wataru is forced to confront the question of whether he can protect the people he cares about while surviving the collapse of the city around him.