What the back of the book says
What I thought
Revenge.  The word rings in Casimir's mind.  He has laid his plans for a decade - ten years among the scruffy children, the rats and the fleas of an orphanage.  At last Casimir sets his intricate scheme into motion, seeking glorious revenge upon the man who slew his mother and made him as orphan.
But revenge is a merciless master.  To slay his nemesis, Casimir summons a dark and powerful curse.  And when that terrible curse is summoned, he must confront the greatest foe of  all..... himself.
Heart of midnight is an excellent Gothic horror book.  Lots of neat gore and other stuff to keep the kids pacified.  I highly recommend this book.