Stoneheart

When twelve-year-old George Chapman smashes the head of a stone dragon outside the Natural History Museum, he accidentally awakens an ancient, dangerous power that brings the city's hidden magical world to life. Stone creatures pterodactyls, dragons, and other hostile taints pursue him through London's streets, and only a small group of children known as spits can help him survive. George must learn to harness the awakened force, make amends for his reckless act, and battle the monsters before they tear the city apart.