A disturbing dark fantasy dredges the uncanny valley to masterful effect. When his conjuror grandfather dies, young circus dogsbody Mathias stumbles upon a hidden scrap of paper that makes him the target of implacable villains. Pursued by the sinister Dr. Leitner and his not-quite-human servants, Mathias and his few allies (with their own tragic pasts and unsavory agendae) are drawn into the hunt for a horrific secret implicating the most powerful in the land. Despite the arch tone of the opening chapters, the tale is relentlessly grim; goodhearted but hapless Mathias is buffeted across an exquisitely bleak landscape, at the mercy of characters either cruelly indifferent or casually vicious. Even the holocaustic climax offers little relief from the continual abuse, despair and grisly violence, leaving many questions (most particularly the fate of the eponymous mastermind) unanswered. Nonetheless, the taut pace, elegant craftsmanship and shattering originality offer their own undeniable pleasures. Seductive nightmare fuel. (Horror. 10 & up)