The world will never be the same for Jehn Brumal. She has lost friends, family and even her home village. To make matters worse, she is one of a handful who knows the truth about the destruction of Trone Stenan; that a Byrael, one of a pantheon of gods credited with creating the world, banished for being "corrupted," was buried beneath the city. Even though the goliath was eventually defeated, the victory came at a steep cost.

Months later, Jehn struggles to acclimate to her new life as a student. On a seasonal break, she visits her friend and former mercenary, Zoe Agilis, in Siracosta. It is there that they receive an unexpected guest: First Mate Collin Bryce of the Aergaeu who has been dispatched by his captain, Corella Seawise. He comes to them with a harrowing tale and a plea for aid. On their expedition to map the Great Sea, the crew uncovers an ancient ruin beneath the blackened island of Valkenistri and now they are dire need of mercenaries for protection.

It is in the seemingly-abandoned subterranean city where they discover a shrine to Eusen Sinie, the first of the Byrael. Seated within the throne room is a mysterious crowned man of stone that proves far more dangerous than the beasts that hounded their arrival.

In A Prison of Flesh, the sequel to Not Gods But Monsters, Jehn and Zoe must discover what resides in the heart of Valkenistri and also manage to survive it.