Huxley Sparks and the Book of Secrets by Suzy K. Quinn
Welcome to the Black Forest, where fairytale creatures come to life... When Huxley Sparks moves to Germany, he hopes to meet some nice, sensible children who enjoy science as much as he does, and to eat iced gingerbread and Frankfurter sausages. He doesn't expect to see fairies - least of all brutal, war-hungry ones - nor goblins, witches and giant wolves lurking in the freezing underworld. But why can't his Nana, mum and sister see them too? An ancient book which Huxley alone can read may provide some of the answers, but there's no time to lose. As a creepy red-hooded figure kills deer in the woods, an evil king is trying to rise from the depths and turn the sun to shadow. Only Huxley and his new friends can stop him.