From a New York Times bestselling author, a young boy is haunted by a voice in his head in this "epic horror" novel, perfect for fans of Stephen King (Dan Chaon, author of Ill Will). Single mother Kate Reese is on the run. Determined to improve life for her and her seven year-old son, Christopher, she flees an abusive relationship in the middle of the night. At first, the tight-knit community of Mill Grove, Pennsylvania seems like the perfect place to finally settle down. Then Christopher vanishes. Days later, he emerges from the woods at the edge of town, unharmed but not unchanged. He returns with a voice in his head only he can hear, with a mission only he can complete: Build a treehouse in the woods by Christmas, or his mother and everyone in the town will never be the same again. Twenty years ago, Stephen Chbosky's The Perks of Being a Wallflower made readers everywhere feel infinite. Now, Chbosky has returned with an epic work of literary horror, years in the making, whose grand scale and rich emotion redefine the genre. Read it with the lights on.One of The Year's Best Books (People, EW, Lithub, Vox, Washington Post, and more)