The third book in the Printz Honor-award winning series, this gothic, gory novel is "articulately literary, horrifically grotesque, and mind-bendingly complex" (Kirkus Reviews).

When Dr. Warthrop goes hunting for the "Holy Grail of Monstrumology" with his eager new assistant, Arkwright, he leaves Will Henry in Victorian New York. Finally, Will can enjoy something that always seemed out of reach: a normal life with a real family. But part of Will can't let go of Dr. Warthrop, and when Arkwright returns, claiming that the doctor is dead, Will is devastated--and not...

In their final horrific adventure, can Will Henry endure a monstrumological terror without his mentor? "Beyond a simple finale, this is a brave statement about the duplexity of good and evil, and the deadly trap in which all of us are snared" (Booklist, starred review).

Will Henry has been through more than seems possible for a boy of fourteen. He's been on the brink of death on more than one occasion, he has gazed into hell--and hell has stared back at him, and known his face. But through it all, Dr. Warthrop has been at his side.

When Dr. Warthrop fears that Will's loyalties...