The book of accidents / Chuck Wendig.

Long ago, Nathan Graves lived in a house in the country with his abusive father -- and has never told his family what happened in that house. Long ago, Maddie Graves was a little girl making dolls in her bedroom when she saw something she shouldn't -- and is trying to remember that lost trauma by making haunting sculptures. Long ago, something sinister, something hungry, walked in the tunnels and the mountains and the coal mines of their hometown in rural Pennsylvania. Now Nate and Maddie are married, and they have moved back to their hometown with their son, Oliver. And now what happened long ago is happening again... and it is happening to Oliver. He meets a strange boy who becomes his best friend, a boy with secrets of his own, and a taste for dark magic. This dark magic puts them at the heart of a battle of good versus evil and a fight for the soul of the family -- and perhaps for all of the world. But the Graves family has a secret weapon in this fight: their love for each other.