In 1751, Tristan Hart is a brilliant young man of means...who also happens to be a psychopath. When he leaves London to pursue a career in medicine, his obsession with the nature of pain and his obsession with causing it become blatantly clear. Desperate to understand his own deviant desires, Tristan sifts through his childhood memories, memories that are informed by dark superstitions about faeries and goblins and shape-shifting gypsies.