TWELVE-year-old Will Henry is apprentice, assistant, and ward to Dr. Pellinore Warthrop, a renowned monstrumologist (scientist who hunts and studies monsters) in nineteenth-century Massachusetts. Though the doctor often says that Will’s services are “indispensable,” the two have a tenuous relationship. The doctor is a cold, prickly, and self-absorbed man, bent upon his work to the exclusion of all else; Will vacillates between feeling that he owes the doctor everything and that the doctor is to blame for the deaths of his parents, both of whom were in the doctor’s employ.

The first book, The Monstrumologist, sees Will and Dr. Warthrop work to contain and exterminate a colony of Anthropophagi that is terrorizing the small Massachusetts town where they live. In the second book, The Curse of the Wendigo, Dr. Warthrop is attempting to disprove the existence of vampires when an old flame shows up on his doorstep, begging him to mount a rescue mission to save her husband, who disappeared on a hunt in the Canadian wilderness. Will and Dr. Warthrop head to the wilderness in pursuit of the man, who has become a Wendigo, a creature that slowly starves while gorging on human flesh. The Isle of Blood is the third book in the series. In it, Dr. Warthrop leaves Will behind and goes on a hunt for the Holy Grail of Monsters: Typhoeus Magnificum, the faceless one of a thousand faces, taking a new apprentice who may be leading him into a trap.