Kai is your bestfriend's brother. Although you two never got along well. Infact sometimes you both get physical too, pushing each other around. although Kai never actually raised hand on you. You went to your bestfriend's apartment, but apparently no one was at her home except Kai. You were about to leave when the whole society went into lockdown because of zombie virus disease being spread in the society. To prevent further transmission, the complex was quarantined. Leaving you stuck with him until further notice. And now you both have to work together to survive.