With a noose around his neck, Samuel arrives in a forest littered with caution tape and artifacts of the deceased. He struggles to regain his memory while fending off a pack of wolves and the mysterious visitors who seem to know more about this dying world than he does. Major, Kole, and Mara, new companions also trapped in the strange locality, realize they must outrun the ominous cloud eating away at reality. As their world collapses upon itself, Samuel must find a way to escape the Reversion.

The Reversion plucks Samuel from a dying world and drops him into another, a decaying desert wasteland of darkness and peril. As his memories return, Samuel finds himself in another cycle of destruction, and he leads newcomers Jack and Lindsay towards redemption in the mountain stronghold of the mysterious one known as Deva. Finally, as the locality collapses behind him, Samuel realizes his only escape from the Reversion will be putting his faith in The Law of Three.

Samuel and Lindsay arrive on the shores of another reversion and quickly realize their journey is not over. They pass through a portal, slipping into a rotting and decayed city inhabited by an army of the undead and their maleficent leader, his brother Kole. While trying desperately to beat the cloud to the east, Samuel must also face his brother and the inevitable confrontation at the end of the world. Only one will survive the Corrosion.