The elevator doors opened on the thirty-fifth floor.
Eun-soo stepped out into the quiet corridor.
She was still in her morning clothes — a loose ivory top and beige trousers, her hair barely brushed and clipped back in a hurry. She had not eaten breakfast yet. The moment her brother's call had ended, she had sat on the edge of her bed for a few minutes, staring at nothing. And then, before she had even fully decided to do it, she was already in the elevator, pressing the button for the thirty-fifth floor.
She had not planned what she was going to say.
She had not planned to come here at all, not this early.
But here she was.
She stood in the corridor for a moment, looking at the door of Unit 3502.
She told herself this was practical. Her brother wanted to meet Jin-woo this evening, and it was better to say it in person than over a text. That was all.
She told herself that twice.
Then she walked to the door and pressed the doorbell before she could change her mind.
The apartment was quiet for a moment.
Then she heard footsteps.
Steady, unhurried footsteps — the kind that belonged to someone who had been awake for a while already.
The door opened.
Jin-woo stood at the threshold.
He was in a plain black long-sleeve shirt and dark sweatpants, his hair natural and uncombed. In his right hand, he was holding a small saucepan, which he had carried straight from the stove without putting it down first.
He looked at her.
She looked at the saucepan.
"You are heating milk," she said. It was the first thing that came out of her mouth.
"Hajun wakes up at seven thirty," he replied simply. "He does not like it cold."
For a moment, neither of them said anything.
He did not look particularly surprised to find her standing outside his door before seven in the morning. He just looked at her the way he always did — calm, steady, waiting.
"Good morning," she said. "I am sorry it is so early. I needed to tell you something. It will not take long."
He stepped aside. "Come in."
She stepped into Unit 3502 for the first time.
It was a big space, but every corner of it was being used for something.
One side of the room had a long desk with computers and equipment on it, everything arranged very neatly. She could tell a lot of serious work happened there.
The other side of the room had been completely taken over by a five-year-old.
A soft foam mat covered most of the floor. There were building blocks near the sofa, stacked in careful little towers. A small whiteboard on a stand had numbers written on it in chalk — small, neat numbers, written by a small, neat hand.
Eun-soo moved closer to look at the whiteboard.
It was a list of perfect squares. 1, 4, 9, 16, 25 — all the way down to 625, where the last number was written slightly unevenly, as though the hand holding the chalk had gotten tired right at the end.
"He wrote that himself," Jin-woo said from the kitchen, turning the flame down under the saucepan. "Yesterday evening. He wanted to know how far the pattern went."
"How far did he get?" she asked.
"625," Jin-woo said. "And then he asked me what came next and fell asleep in the middle of my answer."
Eun-soo looked at that last uneven number on the board.
Something about it made her feel very soft inside — this tiny evidence of a small boy fighting sleep because he wanted to keep learning.
She turned away and sat carefully on the edge of the sofa.
Jin-woo, without asking, filled a mug with warm barley tea and set it on the counter in front of her.
She was almost certain she had mentioned once — very briefly, during some passing conversation — that she preferred barley tea in the mornings.
She had not thought he remembered that.
She wrapped her hands around the mug and did not say anything about it.
Jin-woo leaned against the kitchen counter and waited.
He was good at waiting. He never filled silence with unnecessary words. He just stood there, calm and steady, and let her take her time.
Eun-soo looked down at her tea.
"My brother called me this morning," she began.
Jin-woo said nothing. He was listening.
"Cha Tae-jun. He manages the hospitality side of our family business." She paused. "He wants to meet you."
A small silence.
Jin-woo looked at the middle distance for a second, thinking quietly. Then he looked back at her.
"This evening?" he asked.
She blinked. "He said this evening, yes. How did you know?"
"You came here before seven thirty in the morning," he said simply. "It seemed urgent."
She stared at him for a second. Then she looked back at her tea.
"He mentioned a business reason," she continued. "Something about AI for the hotel. But—" she paused. "I also think he is curious about you. As my brother."
That last part sat between them quietly.
Jin-woo looked at her for a moment.
"Okay," he said.
Eun-soo looked up. "That is it?"
"Was there supposed to be more?"
"Most people find my brother a little—" she searched for the right word — "a lot. He has a certain presence. He makes people feel like they are being examined."
Jin-woo was quiet for a second.
"I think I will be fine," he said simply.
She looked at him.
She had walked down here this morning carrying a quiet nervousness she could not fully explain. She had expected to spend part of this conversation preparing him, softening the idea of meeting Tae-jun.
She had not expected him to just be completely fine with it.
She did not know whether that made her feel relieved or, in some way she could not explain, a little disarmed.
"Send me the address," he said. "I will be there by seven."
She nodded and reached for her phone.
From down the hallway came a sound.
Not a rustle. Not a slow, sleepy shuffle.
A thud — the sound of small feet hitting the floor with purpose — and then rapid little footsteps, quick and determined, getting louder very fast.
And then —
"TEACHER EUN-SOO!"
Hajun came flying out of the hallway.
He was in his dinosaur pajamas, hair sticking up in every direction, one sock half falling off his foot. His eyes were wide and bright and completely awake, as though the moment some part of his sleeping brain had registered her voice, sleep had simply stopped being relevant.
He ran straight across the foam mat, past the building blocks, and crashed into her with his full small weight — arms wrapping around her middle, face pressing into her side, holding on tight the way only a five-year-old can, with zero hesitation and his whole heart.
"You are here!" he said into her side, muffled and delighted. "You are at our house!"
Eun-soo laughed — bright and warm and completely caught off guard — and her arms came around him immediately, pulling him close.
"Good morning, Hajun-ah," she said, her voice full. "Yes, I am here."
He pulled back just enough to look up at her, his little face tipped all the way up, expression absolutely serious despite the joy written all over it.
"Are you going to have breakfast with us?" he asked.
"I—" she started.
"She is staying for a little while," Jin-woo said from the kitchen, in a tone that was not exactly an invitation and not exactly a statement. Somewhere between the two.
Hajun's face broke into a full, brilliant smile — the rare kind, the one that made his eyes go soft and bright at the same time — and he grabbed Eun-soo's hand with both of his and began pulling her firmly toward the sofa.
"Come and see my numbers," he said. "I wrote them myself."
"I can see that," she said, letting herself be pulled. "They are very good numbers."
"625 is the last one," he told her, with great importance. "But I think 676 comes next. Uncle Jin-woo was going to tell me but I fell asleep."
"You did," Jin-woo said from the kitchen, without looking up.
Hajun sat down on the sofa beside Eun-soo, close enough that their arms were touching, and looked up at her with those serious, bright eyes.
"Is 676 correct?" he asked.
"It is," she said.
He nodded once, satisfied, like a tiny professor whose hypothesis had just been confirmed.
Jin-woo watched them from the kitchen for a moment.
His nephew — who was usually slow to warm up, who took his time with most people, who had spent weeks after losing his parents barely speaking at all — was sitting pressed against his teacher's side, talking about numbers with the ease of someone who had known her his whole life.
Jin-woo turned back to the stove and said nothing.
But something in his expression, just for a second, was very quiet and very full at the same time.
They stayed like that for a little while.
Hajun doing most of the talking. Eun-soo listening to every word like it mattered. Jin-woo moving around the kitchen, heating milk, refilling his coffee, the morning going on around them softly.
Nobody mentioned how early it was.
Nobody mentioned it was the first time she had been inside.
The morning light came slowly through the big windows, falling across the foam mat and the little whiteboard and the sofa where a small boy had his teacher's hand held in both of his, not planning to let go anytime soon.
It was warm.
It was a little messy.
It felt like something none of them had a word for yet.
Eventually Eun-soo said she had to go and get ready.
Hajun immediately looked betrayed. "Already?"
"I will see you at school," she said, smoothing his hair down gently — or trying to. It sprang back up the moment her hand left it.
He sighed in the long-suffering way of someone much older than five. "Okay," he said. Very seriously. Very reluctantly.
She laughed and stood up.
Jin-woo walked her to the door.
"Seven o'clock," he said.
"Seven o'clock," she confirmed.
She stepped into the corridor. The door closed softly behind her.
In the elevator, going back up to the eightieth floor, she stood very still.
She was smiling.
She told herself it was just because Hajun had been so sweet.
That part, at least, was completely true.
The other part — the part about the barley tea, and the calm way he had said she is staying for a little while — she decided not to think about that just yet.
The elevator doors opened.
She stepped out, still smiling, and went to get ready for her day.