The murder of an Imperial diplomat takes Din and Ana into the heart of the Empire's Apothetik division where dissecting Leviathans has led to mental corruption that's no less deadly than the physical corruption Leviathan's spread in their wake. Their case appears to be a simple locked room mystery, except the man seems to have robbed a bank vault containing Apothetik secrets after the time of death. Ana has no trouble figuring out the murder, but untangling the vault theft leads Ana and Din deeper and deeper into the secrets of the Apothetik order responsible for the alterations of Imperial servants that keeps the Empire safe. Local politicians, diplomats, and even the Apothetiks themselves have embraced forbidden practices, all in the name of the greater good. To save everyone in the city and the Empire's pipeline of alterations, Ana must make full use of her own alteration and in the process reveal what she really is to Din.

Every wet season the Leviathans emerge from the seabed and attempt to enter the Empire. Defending the people from the Leviathans is, in fact, why the Khanum started altering themselves using what they could extract from the Leviathans. The brilliant Khanum are long gone, except for the Emperor kept in stasis, but the bureaucracy and military live on thanks to those willing who volunteer for various alterations and serve their people despite the side effects, sterility, and shorter lifespans. Like most who sign up, Dinios Kol is doing it to support his family and he survived the difficult Engraving alteration which gives him perfect recall. But Din has a problem, he's Dyslexic in a world that doesn't know it exists, and can't find a position until Ana Dolabra takes him as her assistant. He's elated until he realizes she's insane. Ana is a brilliant investigator but also a total shut in who needs a talented Engraver to attend crime scenes and then regurgitate everything about it for her. It makes for an interesting symbiosis and their first murder case is a real doozy. An Engineer died when some kind of trees grew out of his chest in a wild burst twenty feet high. It looks like the contagion that springs up near a Leviathan's path but there should be other cases. Is it possible to poison someone with a contagion? As the wet season begins and the Leviathans challenge the sea wall, their case will take them to the Wall itself as a terrorist goes on a killing spree at the worst possible time. Who could possibly want to sabotage the Wall they all depend on?