Miles came home at four-thirty. He shut the front door, set his keys and wallet down on the mantel, kicked off his shoes, and shrugged off his bag. On school nights, he left it laying at the bottom of the stairs, right where he could snatch it in a hurry and be off with a granola bar in hand and his water bottle in the other. And this afternoon was no different: he set the bag at the bottom of the stairs and went downstairs, to the kitchen. “Miles?” his mother called. He st