The story follows a group of high school students and the school's nurse as they deal with a worldwide catastrophic event known as the "Outbreak". As the cast tries to survive the zombie apocalypse, they must also face the additional threats of societal collapse, in the form of dangerous fellow survivors, and the possible decay of their own moral codes.
After witnessing a brutal attack on some teachers at the front gate, Takashi Komuro rushes to warn his friends and escape to the rooftop.
As the other survivors fight and hide from zombies, Rei continues trying to contact her father.
News reports reveal that the infection has become a pandemic and entire nations are in chaos. The decision is made to group up, search for others, and escape the school grounds.
After being separated from the group Takashi and Rei discover that the living dead aren't the only threat to their continued survival.
Traffic out of the city comes to a complete stop and tension on the bus continues to rise. Elsewhere Takashi struggles to find a path across the river.
After taking refuge in an apartment, the group gets themselves cleaned up and take a much needed break from running.
Takashi sets out to rescue a little girl but is quickly surrounded by the living dead.
After crossing the river, the group attempts to find their families.
Saeko and Takashi find a new vehicle to evade the horde of undead in between them and Saya's home.
Tension rises at Saya's house and the group contemplates their future.
Takashi makes a decision and an old enemy appears at the gates.