"It is. Did you ask for an invitation before you went into the Malone's house?"

"Yeah," I said. "I guess I did. It's polite, and-"

"And it's harder for you to work magic in a home you haven't been invited into. You cross the threshold without an invitation, and you leave a big chunk of your power at the door. It doesn't affect you as much because you're a mortal, Harry, but it still gets you in smaller ways."

"And if I was an all-spirit creature," I said.

Bob nodded. "It hits you harder. If this Nightmare is a ghost, like you say, then the threshold should have stopped it cold-and even if it had gone past it, then it shouldn't have had the kind of power it takes to hurt a mortal that badly."

I frowned, drumming my pencil some more, and made some notes on the paper, trying to keep everything straight. "And certainly not enough to lay out a spell that powerful on Malone."

"Definitely."

"So what could do that, Bob? What are we dealing with, here?"

Bob's eyes shifted restlessly around the room. "It could be a couple of things from the spirit world. Are you sure you want to know?" I glared at him. "All right, all right. It could be something big enough. Something so big that even a fraction of it was enough to attack Malone and lay that spell on him. Maybe a god someone's dug up. Hecate, Kali, or one of the Old Ones."

"No," I said, flatly. "Bob, if this thing was so tough, it wouldn't be tearing up people's cars and ripping kitty cats apart. That's not my idea of a godlike evil. That's just pissed off."

"Harry, it went through the threshold," Bob said. "Ghosts don't do that. They can't !"

I stood up, and started pacing back and forth on the little open space of floor of my summoning circle. "It isn't one of the Old Ones. Guardian spells all over the world would be freaking out, alerting the Gatekeeper and the Council of something like that. No, this is local."

"Harry, if you're wrong-"

I jabbed a finger at Bob. "If I'm right , then there's a monster out there messing with my town, and I'm obliged to do something about it before someone else gets hurt."

Bob sighed. "It blew through a threshold."

"So …" I said, pacing and whirling. "Maybe it had some other way to get around the threshold. What if it had an invitation?"

"How could it have gotten that?" Bob said. "Ding-dong, Soul Eater Home Delivery, may I come in?"

"Bite me," I said. "What if it took Lydia? Once she was out of the church, she could have been vulnerable to it."

"Possession?" Bob said. "Possible, I guess-but she was wearing your talisman."

"If it could get around a threshold, maybe it could get around that too. She goes to Malone's, looks helpless, and gets an invite in."