“Are you insane?” Valmont demanded.

“Hell’s bells, man,” I said. “Calm down. The target isn’t going anywhere. You aren’t getting any older. What’s the rush?”

He bared his teeth. “Time is relative, Dresden. And, at the moment, it is running out. We open the vault, today. Either Miss Valmont does so or she dies.”

“Or she sets off the mines and we all die?” I blurted. “Have you lost it?”

“Feel free to wait outside if you are frightened,” he said calmly.

And I realized that I could. I could back out of the room and pull Michael with me. Valmont would have nowhere else to go, no other options, and I knew exactly what she would do, facing certain death—she’d blow the system in an attempt to take Nicodemus and Deirdre with her. Or maybe she would pull off a minor miracle and open the door, in which case we could proceed just as we had before. If she died, the raid was blown and Mab’s obligation to Nicodemus was met or at least delayed—and if I got lucky, maybe it would put paid to a roomful of bad people at the same time. If Valmont survived, I was no worse off than before.

And all I had to do was throw a woman to the wolves. The math said it was the smart move.

“Math was never my best subject,” I muttered. “Michael, get clear.”

He ground his teeth, but Michael had worked with me long enough to trust me when things were tight—and we both knew that not even Amoracchius and the purest intentions in the world would save him from a blast like the one Marcone had rigged. He left.

“I’m not frightened,” Grey said. “I want to make that perfectly clear.” Then he also left the room.

“What are you doing, Dresden?” Nicodemus asked.

“Helping. Stop the shot clock and let us work,” I said, and made sure the manacles were locked tight against my wrist as I strode over to Anna Valmont. “Okay,” I told her. “Let’s do this.”

She widened her eyes at me. “What are you doing? Get back!”

“I’m helping you,” I said. “I’m helping you open this door without blowing anyone to hell. Especially yourself. Also me.”

She whirled the little flashlight up and shone it on the ground at my feet. “Stop!”

It was an ultraviolet light. I barely managed to stop my foot before it came down on a circle of vaguely Norse runes painted on the stone floor, invisible to normal light but picked out by Valmont’s flashlight.

“Stars and stones,” I breathed. “It’s a ward.”

She shone the light around the floor in front of the vault door. There were at least a dozen wards the size of dinner plates in the immediate area around it.

“That’s why the door is different,” I said. “They’ve got passive spells running all over the damned room.”

“I didn’t see the first one until I’d already trampled all over them,” she said. “That suggests, to me, that I’m not the right sort of person to set them off.”

“Give me the light again,” I said, and she shone it at my feet. I bent over and peered down at the ward, examining it carefully. “Good call. These are built to react to a practitioner’s aura. Not real strong—there’s no threshold to base them on. But enough to put out a surge of magical energy.”

“Enough to break a circuit, you think?”

“Definitely.”

“So a practitioner walks on one of them and . . .” Valmont opened the fingers of her left hand all at once, an elegant gesture. “Boom.”

The chatter of automatic gunfire came from upstairs—one of the suits had opened up with an Uzi. Valmont and I both flinched at the sudden sound.

“Christ,” she breathed.

“We have no time,” Nicodemus said. “Open the door, Miss Valmont.”

She swallowed and looked at me.

“Shine the light at my feet, so I can see the way,” I said.

She did, and I picked my way over the wards until I reached her side. “Okay,” I said. “Three things. One, I’m not going to run off and leave you here alone. Two, I’m not going to let him shoot you. And three—you can do this.”

“I don’t know if I can,” she said in a low whisper. “What if this door is more complex than the first one?”

“It can’t be,” I said.

“You don’t know that.”

“Yes, I do,” I said. “Because of the way magic interacts with technology. Marcone’s got all these low-grade wards spread out around the door. Whatever electronics or mechanics are inside it, the more complex they are, the faster the magic in this room would break them down and trip the circuit.” I pointed a finger. “That door has got to be assembled out of simpler parts and far simpler electronics than the original. That’s why it got installed secretly—not to stick an even meaner door on, but to hide the fact that the door has to be less complicated than the original.”

Valmont looked at me for a moment, frowning. “Are you sure?”

“Yeah,” I said. “I mean, you know. In theory.”

“God, Dresden,” she said. “What if you’re wrong?”

“Well,” I said, “if I am, neither one of us will ever know it. Because I’m not going anywhere.”

She stared up at me uncertainly.

I put a hand on her shoulder and said, “This is what happened to the audacity of the woman who stole my coat and my car after I rescued her from certain doom? I remembered you with a little more attitude than that.”