Daniel held the warm envelope against his coat while we listened to the knocking: three blows, a pause, then three more, each one lifting a little coal dust from the shed threshold. My father reached for the door, but Peter slipped past him and went into the yard with one mitten on and the other tucked beneath his arm. We followed him through the cold, my mother carrying the lamp and my grandmother keeping so close to the boy that her skirt brushed his coat. The coal had slid away from the hatch in a crescent, exposing the iron ring, which rose and fell with each knock from below. Daniel knelt to lift it, and Peter caught his wrist. “Ask who it is,” he said, and Daniel put his mouth near the crack and did as he was told.

For a while there was only the sound of someone breathing on the stairs, then a woman answered that she had come for her letters. My grandmother sat down heavily on an overturned bucket, and the little girl took the sheet she had set aside from her bag. Daniel opened the hatch, and the woman climbed into the shed, one hand on the ladder and the other holding a narrow black case against her chest; her hair was pinned neatly, though her shoes were wet through. I knew her face from a photograph in my grandmother’s kitchen, where she stood beside a rosebush with a spade in her hand. She looked at my grandmother without smiling, and my grandmother said her name twice before the woman answered. “I kept calling,” she said, and my grandmother pressed her palms together as if she could warm them.

The little girl gave the woman the damp sheet, and when she opened it, several smaller envelopes fell into her lap, their blue addresses running in the lamplight. She examined them carefully, turning each one over, but her fingers stopped at the last, which had been sealed with a circle crossed by two lines. “This one isn’t mine,” she said, and handed it to Daniel, whose own envelope had begun to pulse faintly against his coat. He laid the two side by side on the bench, and the clock hands on their flaps shifted until they pointed toward each other. From below came the train’s whistle, so close that the lamp chimney rattled, and my father pulled Peter back from the open hatch. The woman put her case over the opening, but the boards beneath it bowed upward, forcing her to brace both feet against the floor.

My mother passed Peter to me and took the envelopes from Daniel, slipping a finger beneath the stranger’s flap before he could stop her. Inside was a photograph of our house with the gate unboarded and the shed standing open; in the doorway was the little girl, older than she was now, holding a watch in both hands. Daniel opened his own letter and found a key wrapped in a strip of paper on which the same blue hand had written, “For the next keeper.” The pressure beneath the hatch eased, and the woman lifted her case away, but no one came up the stairs. The little girl reached for the photograph, then drew back when she saw the watch, its face turned toward the camera and its hands pointing to twelve. In the house behind us, the hall clock struck once, and from the bottom of the stairs my father’s voice called the little girl by a name none of us had heard before.

The postman crossed the road without looking at the house, keeping the envelope raised between two fingers as if the rain might reach it even now. The little girl stepped out to meet him, but he passed her and came up the path, his boots leaving dark half-moons on the stones. My father rose when the letter came through the slot, and Peter caught at the blanket, drawing it up under his chin. The envelope was addressed to number thirteen in the same blue hand as the papers from the girl’s bag, though there was no street and no stamp. My mother picked it up carefully and found a brass impression in the flap, a small circle crossed by two lines. When she held it near the lamp, we saw that the lines were the hands of a clock, both pointing straight down.

Inside was a sheet of paper folded around a single coal-black button. My father knew it at once and went to Peter, who held still while he fitted it to the empty place on his coat; the thread was still attached, stiff with soot, and my mother fetched her sewing box from the kitchen. The letter contained only a few words: “Return what was given before the next departure.” Beneath them was a list of names, most of which had been crossed through so heavily that the paper was worn thin, and at the bottom my father’s name remained clear. My grandmother put on her spectacles and brought the page close to the window, tracing one of the crossed-out names without quite touching it. “That was our neighbour,” she said, “the one who kept asking after letters that never came.” Outside, the postman was back at the gate, tapping its boards with the end of a stick.

Daniel went out to speak to him, and we followed as far as the step, where the morning smelled of wet earth and the coal my father had scattered over the hatch. The postman listened with his head bowed, then opened his bag and showed Daniel its empty lining; when he tipped it toward us, a faint whistle came from inside, and the little girl seized the strap before he could close it. My grandmother took the letter from my mother and crossed the pavement, stopping only when the stick began to tap again. “I sent him away once,” she said to Peter, who had come to stand behind her, “and I won’t do it again.” She pushed the letter into the bag, but it slid back out, its edge curling against her wrist, until my father took Peter’s hand and laid the button on top of the paper. The tapping stopped, and for a moment the postman’s face looked less like a stranger’s than a tired man’s, with rain caught in the creases beside his eyes. He drew the string on the bag and handed the button back to my mother, who closed her fingers over it as the letter disappeared.

By the time we returned to the house, the hall clock had reached twelve, though the morning outside had barely brightened. My mother sat Peter on the bench and sewed the button onto his coat, pulling each stitch tight while my father held the cloth smooth beneath her hands. The little girl gathered her damp papers from the bag and counted them twice, then laid one aside for the neighbour my grandmother had named. When Daniel went to fetch his coat, he found an envelope on the mat beneath it, addressed in blue to number thirteen and bearing no stamp. This one was warm, and when he turned it over, the brass impression on the flap showed two hands pointing in different directions. From the shed came the sound of the hatch lifting, followed by a knock against the underside of the floor.

The conductor closed his watch, and the train gave a small shudder against the platform. My father held Peter closer, but the boy twisted in his arms to look through the window. “He wants his time back,” Peter said, and my grandmother gripped the edge of the bench until her knuckles whitened. She told us that on the night she had first heard the little girl at the gate, she had seen the train waiting below and a man standing beside it with a watch in his hand. He had offered to let Peter come home if someone would take his place, and she had been too frightened to open the gate or tell anyone what she had seen. The little girl set the lamp down beside her bag, its flame bending toward the train as though a door had been left open.

My father put Peter on his feet and asked why his name was on the watch. “Because you came back,” the boy said, looking down at the mittens. A whistle sounded somewhere beyond the low ceiling, and the yellow line brightened beneath my father’s shoes; when he stepped away from it, a second line appeared around his feet. Daniel caught his arm and pulled, but my father’s soles stayed fast against the stone, while the train windows cleared one by one, revealing empty seats upholstered in faded red. My mother went to him and knelt, working her fingers beneath the edge of one shoe, but the leather seemed to have sunk into the platform. Peter tugged at his coat, asking him not to let go, although my father was holding nothing now except the boy’s hand.

The little girl opened her bag and brought out a bundle of damp papers, tied with string that had worn thin at the knot. She spread them on the bench, smoothing each sheet with the flat of her hand, and I recognized the blue addresses that had washed under the shed door. “They go back,” she said, and pointed to the brass label, still caught in my mother’s fingers. My grandmother took it and set it on the nearest paper, where the writing darkened into the name of a street I knew, followed by a number and a date so old that the ink on the page beneath had nearly faded away. My mother lifted the sheet and pressed it against my father’s shoe; the paper went soft at once, and the stone released his heel with a wet sucking sound. Together we fed the papers beneath his feet, one after another, while the conductor watched through the glass and the whistle grew louder, until my father stumbled free and fell against Daniel.

We climbed the stairs with Peter between my parents and the little girl carrying the lamp, leaving the last of the papers scattered across the platform. At the top, my grandmother paused to lower the hatch, but beneath it the whistle stopped, and in its place came a steady tapping, as if someone were trying each step with the end of a stick. Daniel dropped the hatch shut, and my father pushed the coal back over the iron ring before we hurried through the shed and out into the pale morning. The hall clock was ticking when we reached home, and my mother found a blanket for Peter while my father sat beside him, rubbing the coal from his hands with a wet cloth. Only the little girl remained at the door, looking down the road toward a postman who had stopped beside the boarded gate. He was sorting through a leather bag, and when he found what he wanted, he held up an envelope addressed to number thirteen.

My father went into the shed so quickly that Daniel had to catch the lamp before it struck the doorframe. The back wall was only brick, its mortar furred with damp, but my grandmother’s voice came again from the other side, close enough that we heard her take a breath between the boy’s name and the next. “Peter, your brother is here.” My father laid both hands on the bricks, and a patch of soot came away on his palms. My mother picked up the second mitten from the coal and brushed it against her skirt, uncovering a row of crooked red stitches along the cuff. “Did your mother make these?” she asked him, and he nodded without turning around.

The little girl appeared at the gate in her dry stockings, with her bag bumping against her knees, and stood listening beside Daniel. “She went in after him,” she said, pointing not at the wall but at the heap of coal. My father knelt and moved the pieces aside, blackening his sleeves, until he uncovered an iron ring set into the floorboards. Daniel pulled it up, and a square hatch opened on a narrow stair, where the smell of wet wool gave way to warm oil and the sweet smoke of a railway fire. The little girl took the lamp from Daniel and started down ahead of us, holding it so high that its light shook over the low ceiling. My mother caught my father’s arm before he followed and put both mittens into his hand.

At the bottom of the stairs was a platform hardly longer than the shed, with a bench against one wall and a train standing on the other side of a yellow line. Its windows were clouded, but through one of them we could see my grandmother sitting beside a boy in a coat dusted with coal; she had an arm around his shoulders, and he was watching the door. My father stepped across the line, whereupon the door began to slide shut, though there was no conductor in sight. He pushed the mittens into the narrowing gap, and Peter caught them from within, one in each hand. For an instant the brothers held the wool between them, my father bent almost double, the boy bracing his feet against the carriage floor. Then my grandmother put her shoulder to the door, and together they forced it wide enough for Peter to slip out.

He stood beside my father on the platform, small enough that the mittens dangled from his hands, while my grandmother climbed down behind him. My father touched the missing button on Peter’s coat and began to say something, but the boy put a mitten against his mouth. “You waited,” Peter said, and my father gathered him up, coal dust and all. The train door closed with a soft click, and in the clearing window we saw the conductor at last, seated alone with his watch open on his knee. He raised the watch toward us; its hands had begun to move, and beneath them, where the maker’s name should have been, my father’s name was written in blue.

My father turned the mitten over, but his name showed through on the other side, the letters spreading between the threads. He tried to pull the label free, and the wool tightened around his fingers until my mother held the cuff open for him. “Tomorrow,” Daniel said, looking at the date, though the hall clock had stopped some time before midnight. My grandmother took the little girl upstairs to find dry stockings, leaving the rest of us around the bench. My father sat down and laid his hand beside the mitten, palm up, as if measuring it against something he had forgotten. “I had one like that,” he said at last. “My mother knitted it, and I lost it the winter my brother went away.”

We had never heard him speak of a brother, and my mother lowered herself onto the bench beside him without asking why. He told us the boy’s name was Peter, and that they had been sent together to fetch coal on a morning so cold the latch stuck to their hands. Peter had run ahead across the road, taking the mitten to tease him, and my father had gone after him as far as the gate between the houses. “He said there was a train inside,” he remembered, rubbing the heel of his hand over his eyes. “I heard it too, but I wouldn’t go in, so he gave the mitten back and told me to wait.” He had waited until his mother called him home, and afterward everyone said Peter had wandered onto the ice at the quarry, though nobody found his coat or his boots.

A soft knocking came from the front door, three blows spaced so evenly that Daniel went to the window before my father could rise. There was no one on the step, only a line of damp footprints crossing the pavement from the gate, each one smaller than the last. When my father opened the door, the cold entered with a smell of coal smoke, and the mitten slid from the bench onto the boards. He picked it up and stepped outside, ignoring my mother when she called for his coat; we followed him to the fence, where the shed door had closed and a thin light showed beneath it. He put the mitten against the wood, and for a moment nothing happened. Then a small hand appeared through the gap at the bottom, searching blindly until his fingers closed around it.

My father knelt in the nettles and held on while Daniel worked at the latch, which had frozen fast despite the mild rain. Inside, something scraped across the shelves, and a child’s voice said, “You came back,” so faintly that we had to bend close to hear. My father pressed his forehead to the door and promised he would stay, even when the hand began to pull away and the skin beneath his grip grew cold as wet stone. Behind us, the little girl called from the upstairs window that the key was in the mitten, and my mother found the brass label lodged in its thumb. The broken piece turned once in the lock, releasing the latch, but when Daniel pulled the door open, the shed was empty except for a small heap of coal and a second mitten lying on top of it. From somewhere beyond the back wall came the sound of a train door opening, followed by my grandmother’s voice, calling Peter by name.