Withered + Sere - Immemorial Year, #1

Once upon a time, humanity could no longer contain the rage that swelled within, and the world ended in a wave of fire.  One hundred years later, in the wasteland formerly known as America, a broken man who goes only by the name of Cavalo survives. Purposefully cutting himself off from what remains of civilization, Cavalo resides in the crumbling ruins of the North Idaho Correctional Institution. A mutt called Bad Dog and a robot on the verge of insanity comprise his only companions.
Cavalo himself is deteriorating, his memories rising like ghosts and haunting the prison cells. It's not until he makes the dangerous choice of crossing into the irradiated Deadlands that Cavalo comes into contact with a mute psychopath, one who belongs to the murderous group of people known as the Dead Rabbits. Taking the man prisoner, Cavalo is forced not only to face the horrors of his past, but the ramifications of the choices made for his stark present.
And it is in the prisoner that he will find a possible future where redemption is but a glimmer that darkly shines. The world has died. This is the story of its remains.