But I was wrong.

The most humiliating thing in the world would be to have all of those things happen and then have your bra mysteriously snap open while dancing with the aforementioned Blackthorne Boy!

I was one good twirl away from disaster, yet Zach still had a hold of my waist; he was still staring into my eyes.

"I gotta go," I blurted, pulling away.

"Ms. Morgan!" Madame Dabney warned as she walked by.

"I mean," I said, turning back to Zach, "if you could excuse me for a moment." Zach didn't look like he wanted to excuse me—he looked like he honestly wanted to know what was wrong—but I just wanted to disappear and take my disobedient undergarment with me.

I started away again, but Zach held on to my hand.

"Thank you very much for the dance," I said, and pulled away.

I felt the bra slide another fraction of an inch with every step I took toward the doors. (The dress, thankfully, was staying right where it should.)

Liz came toward me and said, "Hello, I don't believe we've met. My name is Maggie McBrayer. I'm a vegetarian, and—"

"Not now, Liz," I whispered, and walked faster.

Near the doors I saw a group of eighth grade girls staring daggers at Macey, who Madame Dabney had forced to foxtrot with one of the eighth grade boys.

Mr. Solomon stopped me and asked which of the guests would most likely be concealing firearms, and it seemed like forever before I was able to slip into the empty foyer and dart up the stairs.

"Can I help you, Ms. Morgan?" Professor Buckingham asked as she appeared on the second floor.

"I just need to go up to my room for a minute, Professor," I said, starting to move around her. But despite her bad hip and arthritic fingers, she was still faster than a girl who was afraid that any sudden movements might send her bra out the bottom of her dress.

"Oh, I'm afraid I can't let you do that, Ms. Morgan," she said, blocking my path. "The headmistress said that all students are to remain downstairs during the examination."

"But—"

"No exceptions, Ms. Morgan," Buckingham warned me, and somehow I got the feeling that Patricia Buckingham was never the kind of operative to let a bra emergency stand in her way.

Well obviously Plan B was the bathroom just past the library, but halfway there I saw a door open, and Dr. Steve started walking toward me.

"Oh, excellent, Ms. Morgan … or shall I say Ms. St. James…" he added with a wink. "I was hoping—"

But I didn't have time for an excellent chat with Dr. Steve—not at all—because I could feel the bra making its way toward my waist. The Grand Hall doors stood open. Anyone could come walking out at any minute, so I blurted, "Sorry, Dr, Steve, I've got to go do … something," and then I did the thing that I do best: I disappeared. I went down a corridor that almost no one ever used and walked deep into the heart of the oldest part of the mansion.

The noise from the party grew faint as I ran; Beethoven gave way to the sound of my feet. I hurried down the old stone corridor, listening, looking, until the party was completely eclipsed by the thick stone walls and dense beams, and I was finally alone. … I was supposed to be alone. But there was Zach, leaning against the wall, and for a second both of us just stood there, staring. A strange look crossed his face. "Hey, Gallagher Girl, I thought I'd find you here."

Which was a very bad thing, because A) He'd only looked a little surprised to see me there—which means I'm predictable; and trust me, for people in the clandestine services, predictability is a very bad thing. And B) I'm pretty sure the bra was only hanging on by a thread—literally! I think it was hooked on the waistband of my pantyhose or something, because I could feel it swinging around my thighs. (Note to self: find out why the Gallagher Academy can manufacture raincoats that double as parachutes, but not a strapless bra that can make it through one covert evening.)

"What are you doing here?" I breathed.

"Looking for you."

"Why?" I asked, even though I was pretty sure he didn't know that I'd actually come there so I could take off my bra and stash it in the secret passageway behind the Gallagher family tapestry. Still, I felt like double-checking.

"Because this is where you came the other day."

"Oh."

"I thought this might be where you come…when you're upset." He stepped closer and put his hands in his pockets, which is Body Language 101 for putting someone at ease, but everything about Zach Goode made me uneasy.

He was handsome. He was strong. And most of all, I knew that even though Josh might have been the boy who "saw" me, Zach knew where my favorite passageways were; Zach knew I was a pavement artist; Zach knew where I sat in class and what I ate in the Grand Hall and who my best friends in the world were. Zach "knew" me—or at least the version of me that Josh would never see.

And that was maybe the scariest thing of all. So scary that I temporarily forgot I wasn't just being cool standing there with my hand on my hip—that my hand actually served a very different purpose—so when Zach cocked his head and asked, "So what is it, Gallagher Girl?" I reached up to touch the cold stone wall.

And my bra landed on my feet.

But I didn't have time to panic or worry about how I was going to have to stand in that very spot for the rest of the semester (or at least until Zach walked away), because a siren pierced the air.

A mechanical voice and the words "CODE BLACK CODE BLACK CODE BLACK" sounded.

And then the lights went out.

Chapter Seventeen

The sirens blared, piercing our ears, and the words "CODE BLACK CODE BLACK CODE BLACK" echoed, running together as they reverberated down the long stone hall.

Beside me, the tapestry that bore the Gallagher family tree was moving, sliding slowly between a gap in the stones that then sealed itself as if it had never been there at all.

The only light in the corridor was the moonlight that shone through stained glass windows, but even that was disappearing as thick steel doors slid over the glass.

Although normal protocol says that students are supposed to report to their common rooms in the event of a Code Black, nothing about that night seemed normal at all, so I grabbed Zach's hand and started running toward the Grand Hall as quickly as my high heels would allow.

When we passed the recycling bins at the end of the hall, a container marked BURN—CLASSIFIED MATERIALS ONLY burst into flames.

The vending machines that double as secret entrances to the science labs sank into the floor and were covered with stones identical to the ones that lined the corridor.

And then, one by one, a series of lanterns that hung almost unnoticed along the corridor sprang to life, their pale yellow glow filling the darkness.

"I thought those were for decoration," Zach yelled through the pulsing sirens.

"If everything goes right, they are."

"So this means …"

Formally attired men and women from the maintenance and security departments ran past us, but didn't stop.

"Something is seriously not right."

Bookcases slid into walls, doors swung closed, locks slid into place, and I struggled to yell over the sirens.

"It's security protocol," I said. "There must have been a breach. The whole system goes into lockdown—nothing gets in."

Then, as if to prove my point, steel doors fell from the crown molding, sealing the hallway behind us. "And nothing gets out."

As we ran past the library, I noticed motion through the glass panes and saw that the bookshelves, the couches—the entire room—was spinning, sinking, spiraling into the floor, disappearing before my very eyes.

"Does this happen a lot?" he asked, and the answer was maybe the most terrifying thing of all.

"No."

When we reached the foyer I saw that the front doors had been covered with the kind of metal used on space shuttles and nuclear missile silos. Emergency lights burned in the rafters, casting an eerie red glow over the place I knew well but barely recognized.

I rushed toward the doors of the Grand Hall, but then the sirens stopped. Silence filled my school like a tomb.

The doors to the Grand Hall suddenly swept open, and a hundred pairs of eyes and at least a dozen very powerful flashlights pointed right at me. I squinted and shielded my face against the glare. And that's when I realized that Zach was no longer holding my hand. I glanced behind me, but he was gone.

"Ms. Morgan," Buckingham exclaimed when she saw me standing alone in the dark, deserted foyer. "Exactly where have you been? There is an exam taking place, Ms. Morgan—not to mention a Level Four security infraction. Now, why weren't you in the Grand Hall with your classmates?"

But before I could answer, I heard a voice call, "Cameron!" I looked to the balcony overhead to see my mother staring down. "Come up here. Now!"

The Gallagher Academy is protected by lots of things: Our walls. Our legends. And some very impressive electrical gadgets that block any and all electronic frequencies from penetrating our air space. But that night, something—or someone—had tried to get in. Or tried to get out. So it wasn't any wonder my legs felt a little unsteady as I started up the stairs.

Professor Dabney stood at the top of the stairs, shining a light on the second-story landing, and one look at her stern expression was enough to tell me that this was no drill.

I turned into the Hall of History, where I had seen display cases spin around and disguise themselves for the benefit of strangers: but that night they weren't hidden—they were locked behind reinforced steel doors; walls had swallowed shelves whole, and Gillian Gallagher's sword had sunk into a vault, protected, secure in its place as our most precious treasure. It was a side of my school I'd never seen, and even though I had always known that a Code Red protects us from strangers, and a Code Black protects us from enemies, the difference had never seemed so big until then.

"Cameron," my mother called from her office doorway— not Cam, not Cammie, not sweetheart or sweetie or honey or … Well, you get the picture. We were in full-name territory, and personally, I was starting to wish the big, honking sirens would come back.

"Mom, I didn't do anything!"

But instead of a show of motherly support, Mom stepped aside and said, "Come in."

Her bookshelves had been sealed with titanium shutters, her filing cabinets had disappeared into the floor, and in the corner her burn box was still smoking, but I couldn't look away from my mother, because the expression on her face wasn't disappointment or anger, but something no girl ever wants to see on her super-spy mother's face: fear. She sat behind her desk, more headmistress than mother now.

"What happened?" I heard the panic in my own voice. "What's going on?" I asked.

"You left the Grand Hall tonight?" The voice behind me made me jump, and I turned to see Mr. Solomon leaning against the bookcases behind me, arms crossed just like I'd seen him do a hundred times in class. Somehow, though, I felt I was about to hear a very different type of lecture.

"I didn't do anything," I said again, because even though I've been behind my share of Gallagher Academy security infractions, I have never managed anything greater than a Level Two. (I know—Liz hacked into my student file and told me.)