The doors of the dome closed behind the students with a deep metallic sound.
The interior was far larger than Thomas had imagined. A circular space, as tall as a hangar, illuminated by white lights falling from high above. The floor was made of dark steel, and at the center there was a huge sealed hatch that seemed to lead to another level.
Professor Anderson walked to the middle of the room.
"Good."
Her voice echoed faintly through the metallic structure.
"Before anyone enters the simulation, there is something you need to understand."
She pointed to the hatch in the center.
"Behind that door is a partial reconstruction of an Impossible City."
The students glanced at one another.
"It is not perfect," Anderson continued. "But it is accurate enough that many experienced explorers have been injured inside it."
The murmur grew louder.
Anderson walked toward one of the side walls and pressed a panel. A door opened with a hydraulic sound.
"You have ten minutes."
She stepped aside.
"You will find equipment in there."
The students looked inside the room.
There were shelves full of objects: tactical backpacks, knives, flashlights, sensors, ropes, pulse pistols, breathing masks, cartography devices, small drones, biological scanners.
Too many things.
"Choose what you think is appropriate," the professor continued.
"Impossible Cities do not offer second chances to gear up."
She crossed her arms.
"In the real field, what you carry in your backpack may decide whether you live or die."
Daniel gave a low whistle.
"Well… that definitely raised the mood."
Anderson ignored him.
"The groups will be made up of ten students."
She pulled a small metal box from her pocket.
"The teams and the order will be decided by lottery."
She shook the box.
Small metal pieces rattled inside.
"Each team will have one hour inside the simulation."
She pointed to the opposite wall, where a row of giant screens lit up.
"The rest of you will be able to observe from the monitors."
The screens displayed three-dimensional maps, internal camera feeds, and sensor data.
"You will learn as much by watching as by entering."
Anderson put the box away.
"One warning."
A brief silence followed.
"The first team is always at a disadvantage."
Some students frowned.
"The simulations change with every exploration."
She looked at the hatch.
"But the first team enters without prior information."
Thomas felt the heat in his back again.
He looked at the enormous sealed door, and for a second had the strange sensation that something on the other side…
was listening.
Just then Daniel appeared beside him.
"Well," he said, looking at the equipment room.
"How badly can this go?"
Akira passed by them calmly.
"Much worse than you think."
And he walked straight toward the shelves.
Thomas hesitated for a moment before following them.
The mark on his back burned again.
The hatch doors began to open with a deep sound that traveled through the entire dome.
Beyond them there was no darkness.
There was only a street.
A complete street.
Low gray-stone buildings, crooked streetlamps, balconies of rusted iron.
The sky inside the simulation had a pale tone, as if it were always early morning.
For a moment, no one spoke.
"Well," Daniel finally said. "I wasn't expecting it to be… this much of a city."
Professor Anderson stood behind them.
"Team One."
Ten students crossed the threshold. The moment the last one passed through, the hatch closed with a hard slam. The sound echoed for too long, and the group stood still for a few seconds.
The silence of the place was strange.
It was not the silence of an empty street.
It was a silence that seemed to listen.
The observation room was directly above the dome.
A large space full of screens, maps, and control panels.
On the main wall, several real-time images of the inside of the simulation were displayed. Corner cameras, thermal sensors, three-dimensional maps that updated slowly.
Professor Anderson stood in front of the screens with her arms crossed.
On the central monitor, Daniel's group could be seen advancing down a gray street.
Thomas was sitting in the second row of seats beside Akira.
Both were watching the screen in silence.
Daniel appeared in close-up when one of the cameras turned.
"That idiot always walks first," Thomas murmured.
Akira did not take his eyes off the monitor.
"It's his way of handling fear."
Thomas looked at him.
"You're not afraid?"
Akira took a few seconds to answer.
"Everyone is."
On the screen, Louis was raising his sensor while the group argued about which direction they should take.
One of the students behind Thomas spoke in a low voice.
"It looks easy."
Anderson replied without turning around.
"The cities always look easy during the first few minutes."
Daniel walked a few steps forward.
"So… who's in charge here?"
A tall girl raised her hand.
"Sol Kovacs."
Her voice was firm.
"Explorer."
She pointed to a thin boy with sensors hanging from his belt.
"Louis. Sensors."
The boy nodded.
"Cartography too."
A dark-haired student spoke from the back.
"Zara Benetti. Fauna and biology."
Another raised his hand with a hint of arrogance.
"Victor Hale. Combat."
Daniel lifted both hands.
"Daniel Reyes. Improvisation."
No one answered.
Louis turned on one of the sensors. The device emitted a low beep.
"Temperature stable."
He looked at the screen.
"But… something's wrong."
"What is it?"
Louis frowned.
"The compass."
The needle was turning slowly.
"It can't find north."
Sol studied the street.
"We don't need a compass to move forward."
She pointed ahead.
"Quick reconnaissance. Two minutes. Nobody splits up."
The group started walking.
The houses were too orderly, the windows closed. On some balconies there were clothes hanging that did not move.
There was no wind.
Daniel looked at a crooked streetlamp.
"Does anyone else feel like this city… is waiting for something?"
No one answered.
Zara crouched beside something on the ground.
"Tracks."
Everyone moved closer.
They looked like paw prints, but no known creature walked like that.
They had too many toes.
Louis looked again at the sensor.
"There's movement."
"Where?"
He pointed to a side street.
"There."
Everyone looked, but the street was empty.
"The sensor says something is moving," Louis insisted.
"But I can't see it."
Daniel took a step toward the corner, and at that moment they heard a sound.
Something like bones striking stone, very soft but much too close.
Sol raised a hand.
"Stop."
The group froze.
Something emerged from the side street.
First one leg, then another.
It was the size of a large dog, but its body was made only of white structures, as if it were formed from polished bone.
Then another appeared.
And another.
Three.
The animals moved with a strange slowness.
They did not growl.
They did not seem aggressive.
They simply watched them.
Daniel whispered:
"Well…"
"That definitely wasn't in the Academy brochure."
Louis looked at the sensor.
"There are more."
Sol took a step forward.
"Don't run."
The bone dogs tilted their heads at the same time, as if they had understood the command, and Daniel swallowed hard.
"I think they're studying us."
Silence fell over the street again.
A silence so deep that Daniel had the impression the entire city was breathing very slowly.
And then the dogs began to move.