Butters nodded and went back to his gizmo. Five seconds later, his face brightened. "Hey, whaddya know. It worked. So this circle keeps out magic?"

"And only magic," I said. "Anything physical can cross it and disrupt the barrier. Handy for hedging out demons and such, though."

"I'll remember that," Butters said. He peered down at the gadget. "Harry!" he exclaimed. "You were right! The numbers match up to coordinates right here in Chicago."

"Where?" I demanded.

"Hang on." The little guy punched buttons and frowned. "I have to get it to calculate distance and heading from here."

"It can do that?" I asked.

"Oh, yeah," he said. "Plus AM/FM radio, weather reports, fish and game reports, maps of major cities, locations of restaurants and hotels for travelers, all kinds of stuff."

"That," I said, "is really cool."

"Yeah. You really get a lot for the five hundred bucks on this model." The whole time his fingers flicked back and forth on the gadget. "Right," he said. "Uh, northwest of us and maybe a mile off."

I frowned at him. "Doesn't it tell you the address or something?"

"Yeah," Butters said, pushing more buttons. "Oh, wait. No, you have to buy the expansion card for that." He looked up thoughtfully. "Maybe we could go back and get it?"

"One little burglary and you've gone habitual," I said. "No, it's a bad idea. If a patrol car spotted the broken window there will be police there. I doubt anyone saw us, but there's no reason to take chances."

"Well, how do we find it then?" he asked.

"Turn it off. Then break the circle with your foot and get in the car. We'll head that way and stop in a bit and you can check again. Rinse and repeat."

"Right, good idea." He turned the gizmo off and smudged the chalk circle with his foot. "Like that?"

"Like that. Let's go."

Butters got in the Beetle and we started through the dark, dank streets. After several long blocks I stopped with my lights shining into the awning in front of an apartment building, and Butters got out to repeat the process. He took my chalk with him, dribbled a bit of his blood on the circle he drew, and tried the GPS gadget again. Then he hurried through the rain back into the car.

"More north," he said.

I peered at the darkness as I got moving, going through my mental map of Chicago. "Soldier's Field?"

"Maybe," he said. "I can't see anything."

We drove north and cruised past the home of da Bears. I stopped just on the other side and Butters checked again, facing the stadium. Then he blinked and turned around. His eyes widened and he came running back to the car. "We're really close. I think it's the Field Museum."

I got the car moving. "Makes sense," I said. "Bony Tony had plenty of contacts there. He did some trading in discretionary antiquities."