When students trapped inside Hyosan High School are attacked by classmates infected with a deadly zombie virus. With no food or water, and no contact with the outside world, they must fight for survival and find a way to escape the school and the city. Meanwhile, the authorities have declared martial law, and the ROK Army and the ROKAF keep the school isolated. In the second season, after surviving the Hyosan zombie virus, Nam On-jo, struggling to adapt to her new life, is a college student in Seoul when she suddenly must survive a deadly new zombie virus that is unleashed with new companions and without those who once helped her survive.
