Zach was right. She’d always known we were going to bring her back to the Gallagher Academy. But he was wrong about one thing.

His mother never intended to leave.

“It all burned down,” I sang.

Zach’s eyes went wide. “Where did you hear that song?”

“I went to see your mom last night.”

“You shouldn’t have done that, Gallagher Girl. You should never have—”

“Zach, stop! Listen to me. She’s not leaving.” I gripped his T-shirt and made him look into my eyes. “She’s going to burn the castle to the ground.”

I waited for someone to tell me I was crazy, but then the floors shook. For a moment, the sirens stopped. An eerie, hollow silence followed and no one moved.

“We have to evacuate the mansion,” I said.

“It’s going to be okay, Cam,” Macey said. “I mean, the school has state-of-the-art fire protection mechanisms, right? Liz, right?”

But Liz didn’t hurry to agree. She had her fingers against her lips again, calculating.

“Liz, what’s wrong?” Bex asked.

“It’s probably nothing,” she blurted in a way that meant it was totally something.

“What?” I snapped again.

“It’s just that Dr. Fibs and I have been working on a new kind of power source. We want to take the Gallagher Academy completely off-line in five years, and we think that this has tremendous green technology implications if—”

“Liz!” Bex snapped, bringing her back into focus.

“It’s an energy source,” Liz said again.

“And…” Macey prompted.

“That means it can also be a bomb.”

Before any of us could process what that meant, smoke began to rise up the stairs, sweeping through the hallways and filling the Hall of History. The sirens came again, switching from Code Black to the shrill haunting sound of the fire alarms.

“Fire!” someone yelled from down below.

I watched the doors and windows, waiting for them to open, but the fire alarm must not have been able to override a Code Black, because they stayed barred, trapping us inside.

Panic was starting to grow. Girls rushed toward the doors. The windows. Yells turned to cries, screams that pierced the air. And the younger girls were pushing, going nowhere.

“Tina!” I yelled over the railing.

Down below she was struggling with the doors, trying to get them to open. Eva Alvarez and Courtney Bauer were trying to break the windows.

“They’re locked!” Tina yelled just as the sprinkler system sprang to life. Water erupted from the ceiling, spraying down on us, drenching us, but no one could move to escape it.

“They’re all locked!” Courtney yelled to me.

“Not all of them,” I said.

I ran down the stairs and to the old bookcase I’d first discovered during the spring semester of my eighth grade year. If you pulled out a book called Spymasters of the Ming Dynasty while pushing on the bookcase’s left-hand side, you could make the whole thing spin around, a revolving door into a dusty tunnel that spiraled down into the depths of the school and finally emerged just west of the guard tower on the north side of the grounds.

“In here!” I yelled and Tina rushed toward me. “Go down the corridor. Keep going. It will get you out of the mansion.”

“Munchkins!” Tina shouted, her voice echoing over the cries of the screaming underclassmen, and, instantly, the foyer went silent. “Follow me!” Tina yelled, and the girls did exactly as they were told.

I found another passageway and opened it too, sent Courtney and Eva into that tunnel, doubling the flow of girls fleeing the mansion. And as the halls filled with smoke, they cleared of girls until only my friends and Zach and I were left.

“Cam!” Macey shouted. She was half in the tunnel already, looking back at me. “We have to go.”

But I looked around the hallways. The smoke was so thick I could barely see, and yet I couldn’t stand the thought of leaving.

“I have to find my mom! And Abby! And—”

“They’re outside looking for my mom,” Zach told me, but I couldn’t believe him. I wanted to check her office—to go search her room.

“Gallagher Girl, we have to go. Now!”

In the Hall of History, there was a crash. A piece of the ceiling collapsed on one of the cases. Sparks rained down over the railing of the balcony like sparklers on the Fourth of July.

“Go,” I said, pushing Liz and Bex toward the opening. “Go,” I told Zach. “I’m right behind you.”

I always used to joke that I could walk down the secret passages of the Gallagher Academy blindfolded. Well, that night I got to prove it. Darkness swallowed us. The smoke was so heavy in places that we had to pull our shirts up and cover our mouths. My eyes burned and watered, and the air was so dry it was like breathing sand.

Still, the air grew fresher with every step. The lower we got, the farther we moved from the fires. The passageway was leading to freedom—I could feel it. We just had to keep walking, moving, following the path.

But then I heard the singing.

I could see Bex and Zach up ahead with Liz and Macey. No one was behind me, I was sure. And I stopped just to listen—just to make sure—when I heard the voice again, louder now.

“It all burned down.”

That passageway didn’t branch, I was certain. There was nothing down there but old timbers and cobwebs. There was nothing, I was sure. Except the voice was there. I heard it.

“The knights rose up and killed the kings.”

I backtracked and followed the sound of the voice until I reached a place where the passage widened. I’d never noticed it before and I might not have seen it then, had it not been for the smoke, the way it spiraled there, as if caught in a draft.

I turned to the wall, pushing and pressing until…pop. A door swung open, and there she was.

“Don’t do this, Catherine,” I told her.

Slowly the woman turned. Her hair was greasy and matted. Dirt and grime clung beneath her nails, and yet she smiled at me as if she were a contestant in a pageant.

“Hello, Cammie,” she said.

She sounded so calm—but then I saw Liz’s device in her hands.

“What are you doing with that?” I asked her.

“You know what I’m doing with it,” she said. She pointed to the heavy beams that crisscrossed the ceiling. “Every structural support in the entire mansion can be traced to right here. Did you know that, Cammie?”

I shook my head. “No. I’ve never seen this room before.” And I hadn’t.

As secret rooms go, that one was massive. I was on something of a balcony, looking down on where Catherine stood below. A rickety staircase led toward her, and I studied the space. I think it might have been a cellar once, cold storage for the pre-refrigeration era. More tunnels spiraled out from where she stood, and I knew that one of them must have led to the lake, because there was a wetness in the air. It probably would have been cool there on a normal day, but with the fires raging above us, the dampness felt more like steam.

“How disappointing,” Catherine said, and she sounded like she honestly meant it—like I wasn’t quite the formidable opponent she had thought me to be. “This was always my favorite room.”

Candles burned all around her. It was almost like a temple. A shrine. I could see her retreating to that place during her time at the Gallagher Academy, Catherine’s favorite place for hiding. But I imagine that, unlike me, she never had friends who tried to find her.

“I used to spend so many hours down here. I used to love to get lost. But I don’t have to tell you what that feels like, do I, Cammie? I can see why Zachy likes you. You know what they say, boys always fall for girls just like their mothers.”

I wanted to tell her that she was crazy—that she was wrong. But Catherine and I had both retreated to those dark and secret places. We had pushed through the cobwebs and the shadows in search of the secrets of the past. Yeah. She was right. We had a lot in common. But I knew the kind of girl I wanted to be when I reached the end of the tunnel. I wanted to climb out into the light.

“Don’t you think we’re alike, Cammie?”

“No.” I shook my head and, in that moment, I meant it. I really did. “I think you’re angry. And hurt. And vengeful.” I tried to take a deep breath but the smoke made me cough. “I think you’re incredibly vengeful.”

“Maybe I am.” She looked up at me with a smirk. “But I’m the one with the bomb.”

“You don’t have to do this,” I said. “You’ll never make it out alive. If you set that off now, you’ll die here.”

“You still don’t get it, do you? I won’t die today. And I didn’t die the day I left your precious school—your sisterhood. I died the day I came to it.”

I don’t understand hate. I’ve seen its power. I’ve known its wrath. I’ve even felt it coursing through my own veins, pushing me on. But I don’t know where it comes from or why it lasts, how it can take hold in some people and grow.

I heard a cracking sound, like thunder. Sparks rained down, and I jerked back just as a beam crashed overhead, showering me with smoke and flames, and yet I wanted to run through the falling ash. Stop her once and for all.

“Gallagher Girl!” Zach grabbed my arm and jerked me around to face him. I hadn’t even heard him come up behind me.

“Hello, Zachy,” Catherine said from below, but Zach didn’t even look at her.

“We’ve got to go,” he said, starting to drag me away.

“Zach, we can stop her.” I fought against him with all I had while, down below us, Catherine started singing once again.

“We can still save the school!” I yelled.

A hundred and fifty years of history stood around me. It was the place I loved. It was my home. My destiny. That building was in my veins, and without it, I feared that I might die.

“Zach, we have to stop her!”

But Zach just held me. He looked at me with shock and awe and just a little bit of wonder. In spite of everything, I thought that he might laugh.

“Gallagher Girl,” he told me, “you are the school.”

Then he held my head between his hands and kissed me, hard and fast, breaking whatever trance I was in.

“Zachy!” Catherine called from below.

“Good-bye, mother,” he yelled over the railing. “I will never see you again.”

Then Zach took my hand and together we ran into the passageway. Smoke swelled and I kept running, away from the fire and the woman, fleeing from the ghosts.

And when the blast came, it was like an earthquake, a tsunami of stone and timber and dust that we were trying to outrun.

The passageway crumbled behind us. The beams were rimmed with fire—red sparks shooting through the dry and decaying timbers, racing us toward the cool, clear air of the night.

I still remember seeing the Gallagher Academy for the first time. I’d just never realized I would someday see it for the last time.