Lena is a rare and valued Sin Eater whose function in life is to transform pain and need to pleasure. Dedicated to the service of the god-king Karn the Insatiable, she has spent the last year training in the erotic arts. There's just one problem—Lena has fallen in love with her teacher. The tall, muscular man with wintry gray eyes pushes her limits, constantly testing her. Struggling with her feelings during her final erotic test, Lena wonders how she can leave her beloved teacher and give her heart to a man she's never met to fulfill her destiny as a Sin Eater.