Twisted Christmas Series by Daniel Parsons

After twelve-year-old Toby escapes the cruelty of the workhouse, he dreams of a life of freedom in Victorian London. He joins the Winter Freak Show, a band of travelling acrobats and performers, who put on a spellbinding show each year before Christmas. But all is not well in the City of London. A shadowy force is kidnapping children and only Toby knows the terrible truth. In a race against time, Toby must catch the kidnapper. If he fails, Christmas will never be the same again.