Nineteen-year-old Hikaru Asahina lost everything the day the world ended. Everything, that is, except his childhood friend Ai Kosaka, who has always taken care of him. Now the two of them, along with other survivors, struggle to stay alive in a post-apocalyptic world filled with man-eating zombies.  And when Ai confesses to feeling something more for Hikaru, it changes everything. After all, the more precious someone is to you, the harder it is to lose them. In a world like theirs, is something like love even possible?