After three years infiltrating the Crown's intelligence network, followed by a long and treacherous journey home, Farris has finally arrived at Penance: the Simian City of Steam.

However, much has changed while he was away. Where he was once at the right hand of the Silverback - the leader of the Simian separatist movement - now Farris watches from afar as his old comrades whisper in the shadows about secret plans and advanced weaponry.

Meanwhile, the Sons of Seletoth, a fringe religious sect, has suddenly come to prominence. The ruined Tower of Sin, once the epicentre of Simian ingenuity, now houses these preaching fanatics and their many followers. Worse still, the once atheistic Silverback has now aligned himself with these zealots, but to what end?

Now, Farris has found himself distanced from the separatist movement at this critical time: the Human kingdom has already attacked Penance, and the Simians are ready to march. But Farris fears that even Simian technology will be no match for Human magic...

... and to the south, there are rumours that the dead have risen from their graves.