Elis leads a gray, strictly regulated existence in a city enclosed by high walls - one of the last refuges after a devastating virus outbreak. The WMRO, whose vaccine has saved humanity from extinction, holds the reins of power. Elis sees no future for himself and his forced labor in a WMRO clinic - his only glimmer of hope is the patient with the code RA-1/N, whom he calls Rain.

When Rain is to be taken away and put into a testing phase, Elis realizes that the patients on the ward are not being healed, but are destined for something far darker. In a moment of impulse, he decides to free Rain, and promptly gets caught in a whirlwind of truth, violence, and inhumanity. While the WMRO does everything to get RA-1/N back, Rain embarks on a journey through a world he has never seen, a journey to find himself, always by Elis' side, without whom he would never have known what it means to live.