The doors stood open on a station with his name on it.

WONSEO, said the wall. White tiles, blue trim, the exit stair lit at the far end like a promise.

"Now arriving, Haedong," said the slot in the conductor's face, in the sweet canned announcer voice.

His signal. His wall. Everything the rules had taught us, agreeing at once.

Baek-gu stood in front of the open doors and did not move.

"Baek-gu-ssi." Minseo's voice was careful. "That's your call. Wall and voice. That's the pattern."

"I know the pattern."

"Then why are you still on the train?"

"Because Dalbit to Wonseo is four minutes." He said it without turning around. "There's a hill. The train slows on the grade. Every night for six years I raced this line on the surface streets, and I beat it exactly when it hit that hill. Four minutes, station to station. That," he pointed at the glowing platform, "took ninety seconds. Flat the whole way. No hill."

The chime was still going. Soft. Patient. Somewhere behind us, unhurried, the conductor's shoes went tock, tock on the floor.

"The rule held twice," Chae-a said quietly. "Dalbit passed clean. If you skip your real stop..."

"I know what happens." His hands were shaking. He put them in his jacket pockets so we would stop seeing it. "A punched ticket opens no doors. I know."

...He knows better than any of us.

Haru had her fingers wrapped around the seat rail, white at the knuckle, watching him. Mu-hyeon had shifted his weight forward, ready to grab or ready to shove, and I honestly don't think even he knew which.

The chime began to slow.

"Baek-gu-ssi," I said. My mouth was dry. "Clock or wall."

"The wall's a liar." He stepped back from the doors. One full step. Then another, until his back hit the pole. "The voice is a liar. The hill can't lie. It's a hill."

The doors closed on the station with his name on it.

The platform slid away, white tiles, blue trim, the lit stair, all of it, gone into the black of the tunnel. Nobody breathed.

No window printed. No arrival. No punishment. Nothing.

"...If that was real," Minseo whispered, "it would have said something. Wouldn't it? It always says something."

"It says something when a passenger arrives." Chae-a's eyes were fixed on the dark glass. "Nobody arrived. That proves nothing yet."

Baek-gu slid down the pole until he was sitting on the floor of the aisle, legs out, like a man at a bus stop. He looked at his watch.

"Four minutes from Dalbit," he said. "We're at two ten. If I'm right, there's a hill in the next ninety seconds. If I'm wrong."

He didn't finish it.

"Count," Mu-hyeon said. "Out loud. We'll count with you."

"Two thirty," Baek-gu said.

The wheels ran flat and even. Chatter, chatter, chatter over the joints.

"Two forty five."

Flat.

"Three."

Flat, and my heart was climbing into my throat, and Haru had crossed the aisle and sat down on the floor next to him, shoulder to shoulder, saying nothing, and that was when the sound changed.

The motors dropped a note. Then dug in. A long, low, straining whine, and the whole car tilted back, just barely, just enough, and the joints slowed. Chatter. Chatter. Chatter.

Baek-gu closed his eyes.

"That's the hill," he said. "We're going up."

Nobody cheered. Haru knocked her shoulder into his, once. Minseo let out all her air in one long breath. Mu-hyeon just nodded, like a man confirming a delivery.

"Six years of night routes." Baek-gu's voice had gone thick. He coughed it clear. "The company trains its people well."

The train crested the grade. Coasted. Slowed.

Light rose in the windows, and the wall said WONSEO, and it had taken four minutes, and this time the tiles had water stains and a dead vending machine and a crooked bench, the ugly real face of a real place.

"Now arriving, Haedong," said the slot.

"Yeah, yeah." Baek-gu got to his feet. He picked up his helmet from the seat where it had ridden beside him all night, held it, and then didn't put it on.

He set it down on the seat.

"Hold that for me," he said, to no one of us in particular, to all of us. "Company property. Now you have to come back and return it."

"Baek-gu-ssi," Haru said, "that's not how..."

"That's exactly how." The chime sounded. The doors opened on the real Wonseo. He stepped over the gap, turned on the platform, and gave us a full, formal, two-finger salute, delivery rider to the whole world.

"First one to the surface buys nothing," he said, "because everything's free now. I win either way."

The doors closed. Through the glass we watched him walk toward the stair. He was whistling. We couldn't hear it, but you could see it, the shape of his mouth, the bounce in his step going up into the gray light.

[A passenger has arrived.]

[The binding of passenger Ryu Baek-gu has been extended.]

[Remaining aboard: 5.]

Haru picked up the helmet and put it in her lap and held it with both arms, the way you hold a cat that wants to leave.

* * *

The tunnel took us again.

For a while nobody talked. The conductor stood at the far end of the car, gloves folded, face like the inside of an eggshell, and I made myself stop looking at it.

"Seojin." Haru's voice was strange. Small. "Can I ask you a weird one?"

"Those are the only ones you ask."

"Do you ever dream about people you know?" She was looking at the helmet, not at me. "Because I keep getting this thing. Since the kindergarten. Like a dream I lost the ending of."

Something cold moved in my chest.

"There's a kitchen," she said. "Tile floor. And the section chief. Insik-ssi. He's running toward the kitchen, and I want to yell at him, don't go that way, that's the wrong way. And then it's gone." She finally looked up at me. "He's never been in a kitchen with me in his life. Why do I know it's the wrong way?"

Because you watched him die there. Because he broke toward the kitchen and the fox took him and you screamed, in a night that got unwritten, that no one is allowed to keep but me.

I opened my mouth.

The cold came up my throat like a hand closing, ink pooling behind my teeth, patient, and I knew, the way I knew by now, that the next word would drown.

I closed my mouth.

"...Sorry," Haru said. "Weird one. Told you."

"No." My voice came out level. It cost everything I had. "Dreams are like that. Bad endings you can't check."

"Yeah." She looked back down at the helmet. "It didn't feel like a dream, though. It felt like homework I forgot to turn in."

I sat there beside her and said nothing, and being silent was the loudest thing I have ever done.

* * *

"Haedong," Chae-a said, standing, before the wall even lit. She had her ticket out, held flat in two fingers like a blade.

The station rose in the windows. The slot opened.

"Now arriving, Myodong."

Her signal. She was already at the doors.

"Chae-a." Minseo half rose. "Straight up the stairs. Don't wait around down here."

"I never wait around." The chime sounded. The doors opened. She stepped over the gap, then turned, one hand on the door edge, and looked back at us. At me, actually. Straight at me.

"Tell Dohyeok I figured something out," she said. "About the running. Which way people run. Tell him I want to say it to his face, so he'd better be there."

"Tell him yourself," Haru said. "You'll beat us up top."

"Then tell him twice." Something almost soft crossed her face and was gone. "People should hear that kind of thing twice."

The doors closed. She didn't wave. She was already walking, fast, chin up, toward the stair.

[A passenger has arrived.]

[The binding of passenger Seol Chae-a has been extended.]

[Remaining aboard: 4.]

Four. Minseo. Haru. Mu-hyeon. Me.

The train pulled into the dark, and the dark felt bigger with fewer of us in it.

Minseo stood up. She smoothed her jacket down with both hands, the way I'd seen her do outside the ward doors, a nurse assembling herself before bad news.

"Next one's mine," she said. "Myodong. The hospital stop." A breath. "The train's taking me exactly where I already go. So it doesn't get to feel like winning. It's my commute."

"We'll wait for the signal together," Mu-hyeon said. "You don't move until Cheonmun. Not for the wall, not for the chime, not for anything."

"I know the pattern."

"Patterns held twice," Haru muttered, arms tightening on the helmet. "Everything in this city is a teacher."

Tock.

The sound came from the far end of the car.

Tock. Tock.

The conductor had been collecting the whole ride, punch flashing over empty seats, paper crescents drifting down like snow, always the seats, only the seats. I had stopped watching. That was a mistake, because you should always watch a thing right up until it changes.

It had stopped at the empty rows.

It was walking up the aisle. Toward the four of us. White gloves loose at its sides, punch swinging on its little steel lever, the slot in the eggshell face hanging open and breathing, and it did not stop at any seat at all.