The entrances to the Boylston Street T station are housed in two small, narrow concrete buildings—one for the inbound track and one for the outbound—on the edge of Boston Common. Roxana said her ex had explored the old tunnel from the inbound station, so that’s where I headed. I pulled open the glass door and trotted down the stairs. The warm scent of the subway, exhaust and oil and urine, puffed up to meet me. Kane glided down the staircase beside me, silent as a shadow, keeping close to the wall. Near the bottom, he waited, crouching. I went over to talk to the attendant, who sat by the entry gates in a folding chair. He wore a tweed cap with his MBTA uniform and looked to be in his sixties.

“What time is the last train?” I asked, positioning myself between him and the stairs.

He checked his watch. I didn’t turn around, but I could feel Kane dash from the staircase.

“Should be through in about five, six minutes,” said the attendant. I thanked him and bought a ticket from the machine. I fed the ticket into the fare gate and passed through to the platform.

“Have a nice night,” the attendant said.

“You, too.”

“I will soon as I get home.” He grinned, displaying a gold tooth.

The narrow platform faced the tracks, where the train would arrive. At the back of the platform was a display of some old trolley cars, from when the T was called the Boston Light Railway. I pretended to be interested in them. The trolley in front of me was orange and cream, a bit dented and old-fashioned but not all that different from a modern subway car. The old trolleys sat on tracks that disappeared into a tunnel that ran behind the wall, curving out of sight. Was that the abandoned tunnel? I didn’t see any other candidates.

A fence separated the platform from the trolley display. It would be easy enough to climb except for one thing: The station attendant was watching me.

I turned my back on the old trolleys, strolled to the edge of the platform, and peered down the tunnel, like I was impatient for the train to arrive. I glanced at the attendant. He still watched me—there wasn’t much else to look at this time of night. I smiled. He smiled back, his gold tooth catching the light. I put my hands behind my back and rocked impatiently on the balls of my feet.

A rush of warm air ruffled my hair, and I heard a distant rumble. The breeze got stronger as the train approached. A few seconds later, I could see its headlight. I walked down the platform, away from the entry, like I wanted to get on the train near the driver.

The attendant stood and folded his chair. As soon as his back was to me, I vaulted the fence and scrambled behind one of the old trolley cars. The last train rolled into the station, brakes screaming, and slowed to a halt. I heard the doors slide open and footsteps cross the platform. Warning bells bonged, and the doors slid closed. The train revved, then pulled away from the station. I waited, rubbing my right wrist. Even with the splint, I’d hurt it again climbing over the fence. A shapeshifter can heal a broken bone within a day or two, but not if I kept reinjuring it. I needed to be more careful.

Within two minutes the station was silent. I crept along between the antique trolley cars and the wall, until I stepped into the tunnel beyond the display. The tunnel curved to the left; a triangular head poked around a corner on the right. Kane was waiting for me. He stood in a narrow corridor that led back into the station, coming out behind the stairs. Roxana had said part of the tunnel served as an emergency exit; Kane had discovered the easy way in.

As we moved farther into the tunnel, I pulled out a silver knife and held it ready in my left hand, my fingers tight on the grip.

The tunnel was a narrow, arched passageway, just big enough for a trolley to clear the walls. Lights, spaced every twenty feet or so, cast a yellow glow over the concrete. The old track was still embedded in the floor, but the place was swept clean. Nothing about the tunnel suggested a hidden lair for the ancient undead. It looked like what it was: a clean, well-maintained emergency exit.

Even so, I got that squeezed-in feeling, the weight of the walls and ceiling pressing on me. It wasn’t as bad as crawling into Deadtown the back way or being stuck deep in a pitch-black slate mine, but the constant pressure made me crave air and space.

Focus, Vicky. Watch for the bad guys. I shook off the claustrophobia as best I could, took a deep breath that wasn’t deep enough, and moved forward.

Kane went first, and I was happy to let him lead, with his sensitive nose and keen hearing. He’d be able to smell trouble before it leapt out snarling at us.

Regularly spaced, arched indentations appeared along the walls. The indentations were both narrow and shallow, no more than a foot deep. Perfect for a worker to squeeze into when a trolley passed, but lousy for hiding. Good. The fewer hiding places here, the better.

When the curve straightened out, I could see a long way down the lighted tunnel. There was nothing that looked like a hiding place for the Old Ones.

We went swiftly but cautiously through the tunnel. After a few minutes, we came to some stairs leading upward. It was the emergency exit, heading toward street level and safety. Beyond it, the tunnel stretched into darkness.

The walls crowded in a thousand times more closely.

I glanced up the brightly lit staircase, then squinted into the dark tunnel. Kane was already so deep into the shadows that I couldn’t see him. I took the flashlight from my pocket and flipped it on. I pointed the beam straight down at the floor, trying to keep the light as unobtrusive as possible.

A paw appeared in the circle of light at my feet, and then Kane ducked his head into the beam and gazed up at me. I’d never thought of wolves raising their eyebrows, but that was his expression. And I knew what he was thinking: that I could wait here, in the light, as he checked out the tunnel and reported back.

“No,” I whispered, “we stay together. I’m fine.” Kane could probably hear my heartbeat from where he stood, a riotous thumping that sounded anything but fine. “Give me a second.” Okay, so the lights stopped at the emergency exit. I had a working flashlight. And even if it failed, I wasn’t alone. Kane was here. His eyes shone with intelligence and loyalty, telling me I could rely on him.

I willed my heart to calm down. When it slowed to something like its normal rhythm, we stepped past the emergency exit staircase, beyond the light. Kane continued in the lead, and I stayed close behind him. The narrow tunnel’s walls and low, curved ceiling pressed more heavily with the weight of the darkness, and each breath required conscious effort. In, out. In, out. Don’t forget to breathe.

It was slow going. Like the lights, the tidily swept floor ended at the exit, and I had to watch carefully so I didn’t trip on the tracks or the debris that covered them in this part of the tunnel. Every few feet, Kane would pause and look up, his ears straining forward, his nostrils working to sift through the scents ahead. Then he’d put his nose back to the ground and keep going.

I couldn’t smell anything besides mold and the old dust that covered every surface. But that was the scent of the Old Ones, that deep, underground scent of ancient decay. I stayed on edge, unable to tell whether I was smelling an old, empty tunnel or a black-robed, fanged monstrosity about to attack.

Yet nothing did attack. We reached the end of the tunnel without finding any sign of the Old Ones. At the far end, a huge pile of cans, ranging in size from soup cans to ten-gallon barrels, was heaped up against the wall almost to the ceiling. It looked like debris from a landslide. I shone my flashlight on a label. Pear halves. Judging from the dusty, peeling condition of the label and the rust that marked the seams of the can, it was decades old. There were cans of other fruits and vegetables, crackers and biscuits, and drums marked POTABLE WATER. I didn’t think it would be all that potable now.

Homeless settlement? Fallout shelter? Whatever this tunnel had become after it was closed, these supplies had long outlasted whoever had carried them in. I sheathed my knife. The Old Ones weren’t here.

As we backtracked to the emergency exit, the pressure lessened. We were on our way out.

By the exit, I turned off the flashlight, happy to stand again in the lights of the emergency exit. I set my foot on the first step, but Kane leapt up in front of me and blocked my way.

“What?” Fresh air and open sky were calling me, and I was eager to say hello.

He jumped down the stairs in a bound and pulled at the back of my sweater.

Reluctantly, I stepped back into the tunnel and turned around. “Why can’t we go? Did you spot something?”

He stared at the tracks. I did, too, looking for a secret switch or something that might open a hidden door, like the door to Axel’s guest room. I didn’t see anything like that, but after a minute I realized what Kane was trying to tell me. There was only one set of tracks.

“This tunnel has room for just one train. There must be an old track on the outbound side, too.” Kane yipped and ran along the lighted tunnel. After a longing glance up the stairs, I followed him.

Since Boylston Street Station was closed, we could hunt for the other tunnel without anyone bothering us. I was glad the station attendant hadn’t turned out the lights when he went home. The platform was deserted. We walked along the tracks a little way, then crossed to the outbound side. At the end of the platform, we squeezed around a gate and into another disused tunnel. No lights here. I pulled my knife again, shone my flashlight straight down to the floor at my feet. A little ways into the tunnel was a door marked PUMP ROOM. Cautiously, I tried the handle. It was locked. Kane spent a long time sniffing around the edges of the door, but eventually he continued down the tunnel. Although we followed the tracks to the end, we found nothing else besides dust and scattered debris.

No Old Ones here, either.

We crossed back to the inbound platform and followed the route to the emergency exit. This time, we took the stairs to the street-level door. When I pushed it open, an alarm sounded at the same moment the cool night air hit my face. It took only a second to get my bearings—we were on Tremont Street near the Wang Theatre—and move quickly away from the clanging exit toward Deadtown.

“Just to make sure,” I said to Kane as we walked. “You didn’t scent Juliet in there, did you?”

He shook his head.

“Myrddin?”

Another shake.

“What about the Old Ones?”

He stopped and sat on the pavement. He reared up and lifted his shoulders in a canine approximation of a shrug.

“Not sure, huh?” I could understand that. The entire subway system smelled like an age-old tomb.

Kane nodded, and we continued our progress toward Deadtown.

Although the night was chilly, the breeze blowing from the Common felt warm, carrying smells of spring, of damp earth and life stirring. I inhaled deeply, savoring the sweetness that cut through the usual city smells. It was a good antidote for the dust that clogged my lungs.

The tunnel had been the perfect location for the Old Ones’ base—near the final point on the rune, deep underground, old and dusty enough to feel like home to a bunch of creatures that should’ve been corpses centuries ago. But there’d been nothing. It was hard not to feel discouraged. Juliet was still missing, Pryce was one victim away from coming back to life, and Mab’s life-giving bloodstone was still in Myrddin’s clutches.

We did have one advantage, though. Myrddin wanted my life force to revive Pryce. If I showed up at Boylston Street at the appointed time, Myrddin would be waiting for me.

A guaranteed date with a crazy wizard who wanted me dead—some advantage. But it was my best chance to defeat Myrddin and save my aunt.