Robert Holdstock 
Hexing [EPUB ebook] 

Below London, a lost river flows through the ruins of an ancient temple. A group of children unleashes its unholy secret and falls prey to the gruesome wrath of its guardian. But for Dan Brady, their sinister discovery may be a clue to the location of his missing wife and children. Hexed by evil forces, he is prepared to fight to the death. He is . . . the Night Hunter.