"What?" I stumbled over the word us.

"I mean, saw me." She blushed. "I think that's where the popcorn machine blew up when she walked by. Before she popped the clown's bal oon and made the little children cry." How could I forget?

It was hard to find the impressions in the ground under the tal grass. I bent down and pushed the weeds out of the way, but there was nothing. Just a few paper snow cone cups and tickets. As I stood up, I felt the Arclight heating up in my pocket again, and a dul buzzing. I took it out of my pocket, and it was glowing a clear blue.

I waved Liv over. "What do you think this means?"

She studied the sphere, watching the color intensify. "I have no idea. I've never read about them changing color."

"What's up, kids?" Link wiped the sweat off his forehead with his ratty Black Sabbath T-shirt. "Whoa. When did it start with the mood ring action?"

"A second ago." I don't know why, but I started walking slowly, a few steps at a time. As I walked, the glow of the Arclight grew stronger.

"Ethan, what are you doing?" Liv was right behind me.

"I'm not sure." I switched directions, and the color began to fade. Why was it changing?

I turned around and headed back the other way. Sure enough, with every step the Arclight grew warmer in my hand, the vibrations stronger. "Look." I opened my hand so Liv could see the deep blue color radiating from it.

"What's happening?"

I shrugged. "It's like the closer we get, the crazier it goes."

"You don't think ..." She stared down at her dusty silver high-tops, thinking. We were thinking the same thing.

I turned it over in my hand. "Could it be some kind of compass?"

Liv watched as the sphere glowed so brightly that Lucil e was leaping along beside us, like she was trying to catch fireflies.

When we reached a bleached patch of grass, Liv stopped.

The Arclight was swirling a dark, inky blue. I looked at the ground careful y. "There's nothing here."

Liv bent down, pushing the grass aside. "I'm not so sure about that." A shape emerged as Liv brushed away the dirt.

"Look at the lines. It's a door." Link was right. It was like the trapdoor under the rug in Macon's room.

I knelt next to them and ran my hand along the edges of the door, clearing away the remaining dirt. I looked at Liv. "How did you know?"

"You mean, aside from the fact the Arclight is going crazy?" She looked smug. "The Outer Doors aren't that difficult to find if you know what you're looking for."

"I hope they aren't too difficult to open either." Link pointed at the center of the door. There was a keyhole.

Liv sighed. "It's locked. We need a Caster key. We can't get in without one."

Link pul ed the massive garden shears he stole from the bio lab out of his belt. Far be it from Link to put anything back in its rightful place. "Caster key, my ass."

"It's not going to work." Liv squatted next to Link in the grass. "It's a Caster lock, not something on your locker door."

Link huffed as he worked the gardening shears into the crack. "You're not from around here. Isn't a door in this whole county that can't be opened with a set of pliers or a sharp toothbrush."

I looked at Liv. "You realize he makes this stuff up."

"Yeah?" Link grinned up at us as the door opened with a resentful creak. He held up his fist to me. "Pound it."

Liv was shocked. "Wel , that's not in the books."

Link leaned over and looked inside. "It's dark, and there're no stairs. Looks like a pretty big drop."

"Take a step." I knew what was coming.

"Are you nuts?"

"Trust me."

Link felt around with his foot, and a second later he was standing in the air. "Man, where do Casters get this stuff? Are there, like, Caster carpenters? A supernatural construction union?" He disappeared out of sight. A second later his voice echoed up from the hole. "It's not that far down. You two comin', or what?"

Lucil e stared into the darkness and leaped into the hole. That cat must have picked up more than a little crazy, living with my aunts al these years. I looked over the edge, and I could see the flickering light of a torch. Link was standing below us, Lucil e sitting at his feet. "Ladies first."

"Why is it men only say that when it's something horrible or dangerous?" Liv put one foot into the hole, uncertain. "No offense."

I smiled at her. "None taken."

Her silver sneakers dangled for a minute and she wobbled, off balance. I grabbed her hand. "You know, if we find Lena, she may be completely --"

"I know." I looked into Liv's calm blue eyes, which would never be gold or green. The sun lit her hair, as blond as honey. She smiled at me, and I let go of her hand.

I realized she was the one steadying me.

As I disappeared into the darkness behind her, the door banged shut after me, blocking out the sky.

The entrance to the tunnel was dank and mossy, like the one that led from the Lunae Libri to Ravenwood. The ceiling over the stairs was low, and the stone wal s were old and weathered like some kind of dungeon. Every drop of water and every sound echoed off the wal s.

At the bottom of the stairs, we found ourselves at a crossroads. Not a proverbial one but a real one.

"So which way do we go?" Link looked down two very different tunnels. This trip was more complicated than the one to Exile. That had been a straight shot, but this time it was different, and there were choices to be made.