In the future an outbreak of infectious diseases causes the world's population to drop drastically. While the empire is overthrown by a bunch who call themselves 'Existence' the world slowly starts to freeze over, eradicating a vast majority of the viruses and people. The survivors are separated into several large cities enclosed by walls known as the 'Gates'. A new virus is introduced that turns the host lethal once it takes over, it slowly infects the world once more. A girl called Riley Alderman whom was cast outside of her home's walls deemed insane, tries to make her way behind the walls once more but is found out. With the help of her friend Leo Harris and her companion Kiki the trio escape and make their way to Third Gate where their destiny awaits them.