生き残った6人によると

A mysterious pandemic has broken out at Narita Airport and the city is overrun with zombies. Riri Mizukami, a second-year high-school student and member of the softball club, is rescued by Tokyo Uni student Shōtarō Kashiwa and wakes up in a shopping mall, which is not an official evacuation shelter. Riri and her new friends Renren, Shizuku Murahama, Jin Irie, Beast Kashimoto, Sana Mogami, and Ryō Hirasaka have escaped and are living a "special" life.