"Yes," I said. "Tell me."

Minseo didn't start right away. She turned her phone over on the kitchen table, screen down, screen up. Dead black glass. The battery had died on night zero at sixty-one percent and she still carried it everywhere, the way you carry a passport in a country that doesn't exist anymore.

The station kitchen was dark except for the camp lantern turned to its lowest ring. Everyone else was asleep. My legs still ached from the supply run.

"There's a kid," she said. "Was. Is. I don't know which word."

"Okay."

"Ward six. Haedong General. Bed three by the window. Yeo Sangmin, seven years old." She said the name carefully, both hands around it. "Long-term kid. The kind who knows the hospital better than the staff do."

"What was he like?"

That was the right question, I think, because something in her shoulders came down a centimeter.

"A menace," she said. "He kept a notebook. Rankings. Which nurses were soft touches for extra pudding. Real data, updated weekly. I saw it once when he was asleep."

"Where did you rank?"

"I was circled."

"Circled."

"Circled twice. In red." She almost smiled. It didn't finish. "He had one thing he couldn't do, and it was the hall door at the end of the ward. It has a latch. Old building, heavy door, and when it shuts the latch goes click, loud, you can hear it from every bed."

She pressed her thumbnail into the table's edge.

"He hated that click. He told me it sounded like the door was counting him. Click, one kid, still here, locked in. Seven-year-old words. I laughed the first time."

"So what did you do?"

"I propped it open. Every shift. There's a rubber wedge in the supply closet and I'd kick it under the door at the start of my rounds, and Sangmin could see the hallway light from bed three, and nobody got counted." She turned the phone over again. "Three hundred shifts, maybe more. It wasn't even a decision anymore. It was just a thing my foot did."

The lantern hummed. I already knew where this was going, and it had nothing to do with any novel. There are shapes a story makes that anyone can read.

"The night of the eleventh," she said. "We were short-staffed, two admissions came in at once, a med cart tipped in the east corridor. I was running. And at some point I passed the hall door and it was shut and I thought, I'll get it on the next round."

Her voice stayed level. Nurse-level. That was the worst part.

"There was no next round. It was 11:47 before I got back up the stair. And you know what the ward was."

Empty. She didn't say it. Neither did I.

"The door was still shut," she said. "The latch had been clicked the whole time. He spent his last hour counted, and then he wasn't anywhere at all, and the last thing I ever did for him was nothing."

"Minseo. The Turning took the whole city. The door didn't do anything."

"I know that." She looked at me for the first time since she'd started. "I've been a nurse for four years. I can chart it out for you. No mechanism, no causation, a latch does not remove a child from the world. I know the truth top to bottom."

She put her hand flat on her sternum.

"Knowing the truth doesn't move the thing in my chest one centimeter."

...

I opened my mouth.

Nothing came. Not the cold coil in my throat, not the ink. The gag doesn't guard other people's grief. I was free to say anything at all.

I still had nothing. Every wise sentence I reached for came up as paper. That was its own kind of gag, I guess. The regular human one.

So I gave her the only true thing I had.

"The hospital's east of the river," I said. "Baek-gu's mapping routes past it this week. When it's mapped, we'll go. You and me, and anyone you want. We'll walk up to ward six."

"And do what."

"Open the door together."

Minseo held very still.

"It's not a fix," I said. "I know it's not. But the door's still sitting there shut, and that part we can actually change."

She looked down at the dead phone for a long time. Sixty-one percent, forever.

"Okay," she said. Quietly. "When it's mapped."

She got up, rinsed a cup nobody had used, and went to bed. At the doorway she stopped.

"Seojin."

"Yeah."

"Thanks for not saying it wasn't my fault twice."

* * *

The next afternoon I was on a folding chair in the engine bay, folding.

The supply run had brought back a paper bag of receipts. Not on purpose. They ride along in every box like leaves. I was working through them one by one, small squares, into an empty coffee can.

A shadow fell over my hands.

"There he is," Haru said. "Receipts himself. Doing receipts."

"It's tidying."

"It's a ritual. I've watched you. Every scrap of paper in this station ends up a little square." She dropped down cross-legged in front of me, yellow windbreaker rustling. "Teach me."

"It's not a skill."

"Everything's a skill. Teach me or I'll tell Gureum you know dinosaur facts and lied about it."

I handed her a receipt.

"Corners first," I said. "Match them exact. Then one crease, and you set it with your thumbnail. One pass, hard. Don't saw at it."

She matched the corners with her tongue between her teeth, chipped tooth showing. Creased it. Sawed at it.

"You sawed."

"I improved it."

"You sawed. Again."

She did it again. Better. She held up the little square and inspected it like a jeweler.

"Where's this from," she asked. "The folding. You didn't invent this, it's too specific."

"My mother. She ran a shop. She folded every receipt at the end of the night, corners first, thumbnail. I watched her do it ten thousand times." I folded another one without looking. "She's been gone two years. My hands kept it."

"Huh," Haru said, and didn't make it weird, which I was grateful for.

She took another receipt. Corners. Crease. No sawing.

"My brother makes paper cranes," she said. "Makes. Made. I do the same thing Minseo does with the words." She smoothed the square flat on her knee. "Haeil. He's eleven. He's in Mokpo with our aunt, which is three hundred forty kilometers down the 1 highway, which I've checked so many times I could draw the road with my eyes shut."

"Cranes."

"Terrible cranes. Genuinely bad. The wings never match, one's always fat. He'd fold them out of homework he didn't want to do and leave them in my shoes, so at six in the morning I'm standing in the doorway with a math worksheet crane in my hand and I can't even be mad."

She told it smooth. Every corner of the story already creased, like a receipt folded ten thousand times.

"Mokpo's outside the city," I said carefully.

"Mokpo's outside the city," she agreed. "So he's fine. That's just math. The wall or whatever it is goes around Haeseong, and he's three hundred forty kilometers past it, eating our aunt's cooking and folding fat-wing cranes for some other sucker's shoes." She flicked her little square into the coffee can. Perfect shot. "Your turn. Your mom's shop. What was her best dish, if she fed you like shop ladies feed sons."

"Stew," I said. "She made a stew."

"What kind?"

I reached for it.

And there was nothing there.

Not fog, not almost. A hole with clean edges, like a word razored out of a page. I knew there had been a stew. I knew I had eaten it a hundred times, knew it was the thing she made the night I got my acceptance letter, knew all the facts around the taste, and in the middle of them the taste itself was simply gone.

"Seojin?"

"I can't." My voice came out strange. "I can't remember. The kind. I know I loved it and I can't find it."

The engine bay was very quiet. My heart was doing something small and horrible.

Haru looked at me for a second. Then she picked up another receipt and matched the corners.

"My grandmother had a laugh," she said. "I lost the sound of it years before I lost her. Kept the face she made, lost the sound." Crease. Thumbnail. One pass. "You don't have to remember everything about a person to miss them properly. The missing's the real part. The rest is just receipts."

She flicked the square into the can.

"Now show me the double fold. I know there's a double fold, I've seen you do it when you think no one's looking."

* * *

We folded until the light went orange, then gray.

At dusk the bay skylight let go of one square of dull sky, and something in it moved.

White. Falling slow. Side to side, side to side.

"Haru," I said. "Get Mu-hyeon."

The page came down through the skylight's broken pane, drifted the length of the bay, and settled on the hood of Engine 3, square and flat, like the truck had been chosen.

By the time I reached it my phone was buzzing. Everyone's was.

[The Story 'The Last Train' (Mystery, Rank Two) seeks participants. Venue: Gyoha Station, Line 4. The cover opens at the hour of the last train.]

[Minimum participants: six.]

Boots on the stairs behind me. Mu-hyeon's voice, Baek-gu's, Minseo's, all of them coming.

I stood there with a half-folded receipt in my hand and read it a third time, waiting for the part of me that always knew to start knowing.

It didn't.

Gyoha Station. Line 4. Underground.

I've read four hundred and twelve chapters, and not one of them goes underground.