“So, what are we doing here again?” I asked as we walked through the airport.

“I thought I already explained this,” Dad said with a sigh. “Oh well, here we go again.”

He adjusted his backpack before continuing.

“After the war, two countries were completely annihilated, and the survivors immigrated to neighboring nations. It was a tragedy that shook the entire world. After that, the remaining countries decided they had to do something different. They agreed to work toward lasting world peace.”

“How?” I asked.

“As a symbol of that peace—and as a way to make it last—each continent agreed to choose its smartest student and send them to a special school. There, you’ll learn together from one another and from some of the world’s greatest teachers.”

“That’s what all the tests at school have been about,” I interrupted.

Dad nodded. “Exactly. And you were chosen.”

I stopped walking for a second.

“Wait… me?”

“You,” Dad said with a smile. “Which means we’re flying to Paris. Your education will continue at a school hidden beneath the Champ de Mars. The entrance is concealed inside one of the Eiffel Tower’s four legs, and only students, teachers, and a handful of world leaders even know it exists.”

I stared at him.

“And… I won’t see you again until Christmas.”

“What about Thanksgiving?” I asked.

Dad gave a small shrug. “Since Thanksgiving is only celebrated in America, it isn’t recognized as a school holiday. You’ll have to wait until Christmas break to come home.”

We touched down in Paris in the wee hours of the night, with just enough time for me to grab a croissant and Dad to drink a black coffee. I hadn't slept at all on the flight over the Atlantic Ocean. You would think that the most powerful world leaders would be able to book me a private jet, or at least a plane with more comfortable seats, but no. So, as we approached the Eiffel Tower, my feet dragged and my eyelids drooped.

I looked down at the acceptance letter, blinking a few times until the words came into focus. "You must arrive at the School at exactly two hours prior to sunrise. For in-processing, start at the northwest corner of the Eiffel Tower and proceed counterclockwise. Before you begin in-processing, you must say your goodbyes to your parents, guardians, or anyone else accompanying you to the Tower. GOOD LUCK IS NO MATCH FOR SKILL."

This was it. I hugged my dad goodbye, too tired to really feel sad in the moment--though I knew it would hit me later, once I had gotten a good night's sleep. Then I took a deep breath and walked toward the corner of the tower: the northwest leg.

I wasn't sure what I expected to find. It definitely wasn't a collection of random stickers stuck to the wall like a paper collage. No, they weren't random--some of the stickers were single letters, arranged in rows and groups. The letters looked like they had been placed there haphazardly by tourists at first glance, but there was no mistaking their perfect alignment: these were purposeful.

In-processing, I thought. To prove that we're really smart enough to be here.

I cracked the code in three minutes. It really wasn't that hard: they had already given me the key to decode it in the acceptance letter. Using the phrase "GOOD LUCK IS NO MATCH FOR SKILL," I reordered the letters of the alphabet so that each one substituted for a different one. When I was finished, I noted down the hidden message on my phone.

"Next lock is factorial of seven."

Heart in my throat, I made my way around the tower to the southwest side. I had never been good at factorial numbers, but I understood the concept: a number multiplied by every number before it. For seven, that would be... one times two times three times four times five times six times seven. I found a tiny combination lock between two struts of metal and stared at it, putting the right number together in my mind.

5,040. It took a while, but I turned the wheels to those four numbers and suddenly heard a clanking sound from the southeast side: metal shifting and moving, revealing another lock.

This time, I ran to the next leg of the tower. I smiled when I saw the puzzle: a square of nine tiles, each containing a number from one to nine. The magic square. A classic. I rearranged the tiles so that each row and column added up to 15 and was rewarded with another clanking noise. This time it came from much closer, as a small secret cabinet opened up behind the square.

Inside the cabinet were eight bronze keys, each delicately crafted with a map of the world engraved in the top. I took one and wondered where to go next.

Well, the letter told me to proceed counterclockwise, and there was only one leg of the tower left to go, so... I headed northeast. The final leg loomed over me, the moon casting angular shadows from behind it. But I had to keep going. To show them that I really had passed all those tests, and I had what it took to pass one more.

There was no code, math, or riddle here, just a tiny keyhole. I turned the key.

A door slid open in the ground, stone and concrete giving way to a glassy staircase that led into the dark. I shuddered. Then the sound of applause came from down below, and a man walked out to greet me. He looked South Asian, maybe Indian, with enormous glasses and a simple-looking white robe. As I looked closer, though, I saw patterns woven into the fabric. Numbers, equations, math signs--far too many to understand.

"Congratulations," he said with a smile. He spoke with no accent, just the deliberate, precise tone of a totally mastered second (or third? Fourth? Tenth?) language. "You are officially the first to arrive at the School. I'm Dean Bahu, director of student life here. The others will be arriving within the next few hours after their own in-processing, but for now, you must be feeling very jetlagged. Please relax and enjoy yourself."

For the first time since arriving in Paris, I relaxed. I was officially in.

One thing still bothered me, though. I thought back to that secret door behind the magic square on the southeast leg. There were supposed to be seven students at the School, the smartest kids from each continent. So why were there eight keys in the cabinet?

I must have drifted asleep, because suddenly I was blinking awake to find another student walking down the steps. She appeared to be the student from South America.

“Hello. Are you the North American? My name is Alysha Khan, but my friends call me Tallae.” (Pronounced ta lay)

She spoke in perfect English, which surprised me for a moment until I remembered she must be from Guyana.

“Yeah. I’m Elana.” I smiled. “Wait… where did Tallae come from?”

“We have two names in my culture,” she explained. “One is our given name, and the other is the name our family and friends use.”

“Okay, Tallae, that makes sense.” I paused. “What do you know about the eight keys?”

She shook her head. “Nothing. At first I thought I had simply been the first one here, but then I saw you.”

We both fell silent, turning the mystery over in our minds.

Then an Asian boy walked down the stairs.

The boy wore a suit and tie, a harsh contrast to the comfortable travel clothes that Tallae and I had on. Had he really flown all the way from Asia with it on? His hair was short and precisely cropped around his face, and he stopped on the second-to-last stair for a few seconds to study us.

I wasn't sure what to think, but finally he smiled. "You must be from North and South America."

I nodded. "Yep, that's us. I'm Elana, from the United States, and this is Tallae."

"From Guyana," Tallae added. "Georgetown, the capital city on the Caribbean."

The Asian boy joined us on the couch, squaring his shoulders and sitting up completely straight. "Nice to meet you, Tallae and Elana," he said. "I'm Wu Huifeng. In Chinese, my name means Wise Phoenix, so please call me Phoenix so I don't have to listen to your terrible attempts at pronunciation." I couldn't tell if he meant that in an insulting way or not, but the request seemed to be genuine. Phoenix it is.

"Did you have to go through the puzzles, too?" I asked. "With the cipher and the magic square and all that?"

"Not those puzzles." Phoenix drummed his fingers on the arm of the couch. "According to the others, each of us had a different set of puzzles or challenges based on our specific strengths and weaknesses. Mine were logic puzzles using concepts of physics."

"The others?" Tallae suddenly seemed intrigued. "How many are here?"

We were answered by a sudden clattering on the stairs above. A girl with long black hair bounded down the steps two at a time, pausing on the fifth one. She took a deep breath, then vaulted over the remaining five stairs, landing gracefully on her feet.

I realized I recognized her: Skye Paraone, a New Zealander who had gained an Internet following doing extreme sports and stunts. I had seen a reel of her BASE jumping off an ice cliff, deploying a wingsuit, and gliding to the ground after performing some flips and rolls. I wasn't sure how someone who routinely risked her own life jumping from tall objects could be the smartest student in Oceania, but surely the School knew what it was doing.

"Kia ora!" She grinned widely and waved. "I'm Skye! Good to meet two more of you. I think this is really the adventure of a lifetime, yeah?"

Before I could answer, a crash came from the stairs. A ghostly pale boy with curly, tangled blond hair lay on his face on the floor, having tried and failed to copy Skye's jump.

I quickly ran over and helped him to his feet. He blinked blearily, eyes totally blank. I had sympathy after my jet lag experience.

"Thanks..." he muttered. "I'm, uh..." He paused, evidently trying to remember his own name. I hoped he didn't have a concussion. No, his eyeballs looked fine. "I'm Matthew. From, uh, McMurdo Station. My parents study penguins."

Antarctica. To be honest, I hadn't thought about the logistics of finding the smartest student on a continent with no real schools. How many kids were there to choose from? It couldn't be very many. Looking at Matthew, it seemed like the School had just taken whoever they could find.

"What about the other two continents?" Tallae asked. "Europe and Africa?"

"Not here yet," Phoenix informed me. "Since their journeys were the shortest, the School gave them more time flexibility. But the Dean said we'll all meet officially soon."

"And what about the eighth key?" I asked, holding my breath and hoping someone would have an answer.

They all stared blankly at me. Finally Skye spoke up.

"No clue."

“Maybe they decided to add a student for the islands,” Skye muttered, almost as if she were speaking to herself.

“No,” I said, the answer slipping out before I even thought about it, though not harshly. “I had a pen pal in Hawaii, and she said they weren’t doing it there.”

“Perhaps it’s for a teacher,” Phoenix suggested. “A way to prove they’re capable of teaching us.”

“Well, whatever it is,” Tallae said playfully, “we have a mystery on our hands.”

“A mystery about what? The eight keys?”

A new voice echoed through the room.

The European student had arrived.

Now we were only missing one…

Or were we missing two?

“Yes, it’s about the eight keys,” I answered. “What’s your name? I’m Elana.”

“I’m Iker. It’s nice to meet you all.” He smiled. “And I’m glad to see everyone else noticed the keys right away, too.”

Iker. It was an interesting name—not strange, just unfamiliar. I found myself wondering what it meant.

“Yes, me too. Maybe the African student will have some answers,” Phoenix said.

I glanced over at Matthew. He had quietly sat down and looked overwhelmed, as though he couldn’t quite keep up with the rest of us. I felt a little sorry for him.

We talked for another ten or so minutes—mostly Skye doing the talking, actually. We learned that she was Maori, her flight from Auckland had taken over twenty hours, and she was already planning to try and BASE jump off the Eiffel Tower. Somehow I doubted the School faculty would be okay with that.

Eventually the seventh student, the one from Africa, arrived. He walked slowly down the stairs, no doubt taking in the strange sight of the six of us. We were a very odd crowd: Phoenix in his suit, Iker in a gray outfit that blended in with the couch, Skye talking animatedly while the rest of us listened through various levels of exhaustion.

He greeted us in a language I didn’t recognize. I looked blankly at Iker, who shrugged. Tallae stood up and answered in the same language, and then they switched to another language. This one I recognized as French, though I still couldn’t understand what they were saying. I really should have learned more languages than my intermediate level of Spanish before I entered into a school for students from around the world.

Tallae turned back to us while the African boy waved. “This is Abdou. He’s from Senegal. He’s very pleased to be here.”

I whistled, impressed. “You speak French and… what was that first language? Wolof?”

”Yes.” Tallae said it like it was nothing. “Guyana is one of the most multicultural countries in the world. We have people descended from the English, Dutch, West Africans, Indians, not to mention our native culture.”

“So how many languages do you speak?”

“Well,” she started, “speak is a strong word for most of them.”

I blinked.

”I’m only fluent in English, Spanish, Portuguese, Hindi, and Dutch. And French, I suppose, but I only really got good at it a few months ago when I learned I would be coming to the School in Paris.”

“That must be why you were selected for the School,” said Phoenix, impressed. “Not everybody can learn that many languages that quickly.” I nodded in agreement.

Abdou said something else in rapid-fire French. Tallae answered, an interested look crossing her face.

“What is it?” Skye asked. “What is he saying?”

“He saw someone else enter the square and go to the northwest side as he was heading down the stairs,” Tallae said at last. “A girl in a white hoodie. Or at least, he’s pretty sure it was a girl. He didn’t get a great look.”

“So that settles it,” said Iker. “There is an eighth student who was invited to the School.”

“But from where?” I mused out loud. “We each come from a different continent, so what does that leave? Where on Earth isn’t part of any continent? The ocean?”

Matthew raised his hand timidly, the first time I’d seen him move in about twenty minutes. “Maybe they aren’t from Earth,” he suggested.

“Sweet as!” Skye pumped her fist. “An alien student? That would be real sweet, except that aliens don’t exist.”

I was still thinking about my ocean idea. There technically were countries under the ocean—the ones that had been destroyed in the war by terrible weapons previously unknown to humanity. No one lived there now, of course, but that didn’t mean no one from there had survived.

The School was all about recovering from the war. It made sense that they might choose a representative from a fallen country.

All that was just my guess, of course. We wouldn’t know for sure until—

The light sound of footsteps came from the stairs above.

All seven of us froze.

The footsteps were slow.

Not hesitant—careful.

Whoever was coming down the stairs wasn’t rushing. They weren’t nervous about being seen. They walked like they already knew exactly where they were going.

One step.

Then another.

The room went silent.

Even Skye stopped talking, which I was beginning to realize was a rare event.

A figure appeared at the top of the staircase.

A white hoodie.

My eyes widened slightly.

Abdou had been right.

The person paused for a moment, looking down at us. From where we stood, I couldn’t see much of her face, only the shadow of the hood and a few strands of dark hair escaping around the edges.

Then she started walking again.

As she reached the bottom of the stairs, she pushed her hood back.

She was a girl about our age, with dark brown hair pulled loosely over one shoulder and a calm expression that made me feel like she had already figured out something the rest of us hadn’t.

“Hi,” she said.

Her voice was quieter than Skye’s and more relaxed than Phoenix’s. “I’m sorry I’m late.”

“Late?” Skye repeated. “You are aware you were dramatically walking down secret stairs underneath the Eiffel Tower, right? That’s not exactly a normal entrance.”

The girl laughed.

“Fair point.”

Dean Bahu stepped forward with a smile.

“Everyone, this is Nura Hassan.”

She gave a small wave.

“Most people call me Nura.”

I looked around at the others. Everyone seemed to be thinking the same thing.

The eighth student.

Nura noticed our expressions and glanced at the cabinet where the keys had been hidden.

“Ah,” she said. “You found those.”

“You know about the keys?” Phoenix asked immediately.

Nura nodded.

“Yes.”

The room went quiet again.

“Then you’re the eighth student?” I asked.

She looked at me.

“Yes.”

The simple answer somehow created even more questions.

“But…” I hesitated. “How? There are seven continents.”

Nura smiled slightly.

“That depends on what you count.”

Everyone exchanged looks.

“Okay,” Tallae said, sitting forward. “Now I really want to know.”

Nura walked over and sat with us.

“I suppose I should explain. I didn’t come from a continent.”

Skye’s eyes widened.

“Wait. Matthew was right?”

Nura looked confused.

“Who is Matthew?”

I pointed toward the couch, where Matthew immediately looked like he wished he could disappear.

“Antarctica,” he mumbled.

“Oh.” Nura smiled. “No, not Antarctica.”

Matthew looked relieved.

“Then where?” I asked.

Nura was quiet for a moment.

Then she answered.

“The ocean.”

Nobody spoke.

Not because we didn’t have questions.

Because we had too many.

“The ocean?” I repeated.

Nura nodded. “My home was part of a country that no longer exists. The war destroyed it, and most people assumed everyone was gone. But some survived.”

My mind immediately went back to the acceptance letter.

The School was created after the war.

A symbol of peace.

A way for different people to learn from one another.

“That’s why there are eight keys,” I whispered.

Nura smiled.

“Exactly.”

For the first time since finding that cabinet, the mystery finally started to make sense.

But only a little.

Because now we had a new question.

If the School knew about a student from a lost country…

How much else did they know that the rest of the world didn’t?