Seventeen-year-old Taj is the most talented sin-eater indentured by the Guild, a ruthless organization of Mages that runs a lucrative trade absolving the rich.

In the walled city of Kos, Mages have a dark magic that allows them to call forth sin from a sinner in the form of sin-beasts—lethal creatures spawned from feelings of anguish and guilt. Every time Taj slays a sin-beast, an image of the beast scars his skin while the guilt of committing the sin scars his mind. Most sin-eaters can’t take it, driven mad by the process. But Taj is gifted and cocky and desperate—his family depends on his wages, and he’s willing to risk everything for them.

Until Taj is hired to do a job that even he can’t follow through on. Soon, Taj realizes that some sins should never be Eaten. When he stumbles upon a dark plot to destroy the kingdom, Taj must fight to save the princess he loves—and his own life.