Yusuf, eleven years old, vanished from his grandmother's house at three in the afternoon and never came back.

Inspector Huda was sitting in the small room attached to the police station when the grandmother walked in, clutching her phone with both trembling hands. She said, "He sent me three voice messages. In the first he wrote that he's fine, that he doesn't want me to worry. But I don't know where he is."

Huda took the phone and held the speaker to her ear. She pressed play.

The first message, 3:41 p.m. A tired boy's voice, quiet: "Grandma, I'm fine. Don't worry." In the background, a faint clatter, then a smell that couldn't be recorded but was unmistakable in his tone: the sound of an oven, the rustle of dough being kneaded on a wooden board. A few seconds later, a long, sharp whistle. A train whistle.

The second message, 5:12 p.m. A weaker voice: "Getting a bit cold. I'll wait." In the background, the sunset call to prayer rising from somewhere distant, then fading, then overtaken by a metallic sound: iron striking iron, spaced out, slow.

The third message, 7:30 p.m., the last one. His voice hoarse and brief: "Grandma, I'm sorry." In the background, a drop of water falling somewhere vast, its echo arriving half a second later: plink... plink...

Huda put the phone down. Her assistant said, "There's no word that gives away the location." She said, "The words, no. But the sound is speaking."

She set paper and a pen on the table and wrote down three leads:

First: a bread oven and a train, together. That means a bakery near a railway.

Second: the call to prayer heard from a distance, and spaced-out iron strikes. That means an area with workshops nearby, but not in the heart of the neighborhood.

Third: water drops and a deep echo. That means an enclosed, spacious place, with a tank or a high ceiling.

She asked the grandmother, "Did he love trains?"

The grandmother's eyes welled up. She said, "His father was an engine driver on the old Hijaz railway. He died three years ago. He used to take Yusuf to the station every Friday, and tell him about the locomotives."

Huda's eyes widened. She said, "The old station. The one that's no longer in use."

The station stood outside the city, surrounded by an abandoned train workshop and a small bakery still running for the old workers. And behind it, a massive warehouse holding an old iron water tank once used to supply the locomotives.

Huda arrived with her team at a quarter to nine.

Before that, Huda had passed by the small bakery next to the station. The old baker was taking his last loaves out of the oven when she asked him if he'd seen a boy in a blue jacket. He wiped his hands on a towel and said, "Yes. He came around three-thirty. Bought a hot loaf, and asked me: is the old locomotive still in the big warehouse? I told him yes. Then he went on his way. I thought he was just playing."

She asked, "And why didn't you call anyone?"

The baker looked at her sadly. "I thought he was one of the workers' sons, and that he'd come back."

The temperature was dropping below five degrees. Huda glanced at her watch: forty-eight minutes since the last message. Then she ran to her car. The night was cold, the wind howling through the iron. They switched on their flashlights and walked along the tracks.

Along the way they heard a metal wheel rattling on its own along the rusted rails. Everyone stopped. It turned out to be only a piece of iron swaying in the wind. But for the first time, Huda felt real fear. Not of the dark, but of the thought of arriving too late.

One of the officers said, "No sign of the boy."

Huda was listening to something. She raised her hand: "Quiet." Everyone froze. From the direction of the warehouse came a ringing sound: plink... plink... a drop of water falling into empty space.

She walked toward the great warehouse alone. She pushed the heavy iron door, and it screeched open with a long creak. The inside was dark, smelling of rust and dust. She switched on her flashlight. She saw the massive water tank looming like a tower, and beneath it, an old locomotive with no wheels, its door hanging open.

She stepped closer. Climbed two steps. And inside the small iron cab, wrapped in an old blanket, leaning against the driver's seat, Yusuf lay asleep.

He was holding a large black cap bearing the railway's emblem. On the seat in front of him lay a folded piece of paper.

Huda sat down beside him gently. She said softly, "Yusuf... it's Huda. Your grandmother is waiting for you."

He opened his eyes slowly. When he saw her, he jolted upright. He said, "Are you going to take me away?"

She said, "I'll take you to your grandmother. But first, tell me why you came here."

He lowered his head. He said, "I heard my mother and my uncle talking last week. They said they were going to sell the last thing left of my father: the old railway house. I said I'd save the locomotive. I thought that if I sat in it for a whole day... they wouldn't sell it."

He set the cap on his knees and added, "And I'm sorry I lied to Grandma."

Huda sat silently. She felt no urge to scold him. She picked up the folded paper from the seat, opened it, and found a pencil drawing of a large train, and beneath it, in crooked childish handwriting: "To Baba: the locomotive is still here."

She carried him in her arms and walked out into the night. The whole team was waiting at the door. When the grandmother arrived, she ran to him and held him, crying and laughing at once.

In the weeks that followed, after Huda heard the whole story at the police station, she decided to write a special report. She submitted it to the municipality along with photos of the old station. Two months later, a decision was issued to turn the railway house, the warehouse, and the locomotive into a small museum of railway history.

On opening day, Yusuf was the first one through the door. He stood at the front of the hall wearing the big black cap, and said to the photographers in a clear voice:

"This is my father's locomotive. And it's still here."