北沢泰輔(きたざわ たいすけ)'s smile was still in her head. That classroom after school. Third-year, second class, bathed in the glow of the setting sun. He'd bumped his head on the desk while sitting in a child's chair, and yet 北沢泰輔(きたざわ たいすけ) had smiled and said "just a little," in that single moment. 紗彩(さあや) walked home from the daycare center and felt exasperated with herself. It had been days already. Why was she still thinking about it? She'd left Komorebi Daycare just before four o'clock. 凛人(りひと)'s after-school care ran until five. Considering the walk from there to the apartment complex, she'd need to leave by 4:45 to pick him up on time. Which meant she had a little time to spare today. (Maybe I'll kill some time somewhere.) Usually she'd stop by Ootsuka Fish Market in the shopping arcade to buy dinner, then head straight to pick him up. But she wasn't in the mood for that today. For some reason, she just wanted to breathe the air. Her feet turned toward the Nishina River promenade. Seven or eight minutes east from Kasumigaoka Apartments. Down the embankment, and the riverside path stretched out, carefully maintained. The cherry blossom season had passed; now it was a tree-lined path where the green had deepened. On weekends it would be crowded with families and people walking dogs, but at this hour on a weekday, there were few people. Only the murmur of the river could be heard clearly. 紗彩(さあや) descended onto the promenade before the bridge. The river surface glimmered with light. The May sun reflected off the water, wavering. Each time the wind blew, the leaves rustled softly, and with just that sound, she felt the tension drain slightly from her shoulders. (I like this place.) As she walked with that thought, she saw a figure ahead. At first she didn't pay attention. Joggers weren't uncommon. But that silhouette—— Her feet stopped. Gray short-sleeved shirt, black running tights. An elegant running form. And more than anything, that presence. It was 北沢泰輔(きたざわ たいすけ). 紗彩(さあや) instinctively stepped back. Why. There was no need to run away. But her body moved on its own. 北沢泰輔(きたざわ たいすけ) didn't seem to have noticed her. He slowed his pace before the bench along the river, then came to a stop beside it. He did a light stretch, then turned to face the water. 紗彩(さあや) remained frozen. She knew the usual 北沢泰輔(きたざわ たいすけ). Black-framed glasses, neat shirt, quiet and composed tone. Polite with the children, but somehow distant. A teacher who didn't show his emotions. But this 北沢泰輔(きたざわ たいすけ) was——completely different. He was sweating. His shirt was damp around the shoulders. He was catching his breath, staring intently at the river. He wasn't wearing his glasses, or so it seemed; his face was clearer than usual. In his profile, she sensed something——she couldn't quite put it into words, but something like loneliness. Not the 北沢泰輔(きたざわ たいすけ) from school. Not the 北沢泰輔(きたざわ たいすけ) as a teacher. Just one person, standing alone by the river in the evening. (So the teacher makes that kind of face too.) It was obvious. And yet somehow, it didn't feel obvious. Something stirred restlessly in her chest. She thought about calling out to him. But what would she say. "Hello"? "What a coincidence"? That would be the end of the conversation. Wouldn't it be a bother? He was running alone because he wanted to be alone. She took a few steps backward. She could slip away quietly. That way he could have his time alone. She could go home as if nothing had happened. ——That was when 北沢泰輔(きたざわ たいすけ) turned around. Their eyes met. 紗彩(さあや) froze. There was nowhere to hide. No, she couldn't run away. But what kind of face should she make. "……凛人(りひと)'s mother." 北沢泰輔(きたざわ たいすけ)'s voice showed no surprise. Quiet, and nothing more. "[surprised]Oh, um, yes. Um——thank you for your hard work." Her voice pitched slightly higher. When she tried to smile, it felt strained. This was the worst. 北沢泰輔(きたざわ たいすけ) approached her. He wasn't wearing his glasses after all. Because of that, the impression his eyes gave was different. A little softer——or so it seemed. "I run here often." "I see……" Even as she spoke, 紗彩(さあや) was criticizing herself internally. (That's it!? That's all I can say too!?) "It's nice here, isn't it. The sound of the river." "Yes." A brief reply. The conversation faltered. Only the sound of the river continued. Three seconds of silence. To 紗彩(さあや), it felt like thirty. "凛人(りひと) seemed well today too." 北沢泰輔(きたざわ たいすけ) spoke first. His tone was slightly different from before. Just slightly softer. "[gentle]Is that so. ……Thank you very much." Another silence. But this time it was a little softer than before. "I'm sorry for getting in your way. I should have turned back." "No." With just that, 北沢泰輔(きたざわ たいすけ) turned back toward the river. 紗彩(さあや) found herself looking at his profile. The evening light fell at an angle, and the reflection from the river surface wavered. 北沢泰輔(きたざわ たいすけ)'s eyes caught that light, narrowing slightly. That air of loneliness she'd sensed from a distance before——it was still there. (What is he thinking about?) As she had that thought, she became aware that her chest was rising and falling faster than before. Thump, thump, thump. Wait a second. Why. There's nothing. Just happened to meet the teacher by the river. Haven't even had five exchanges of conversation. So why is my heart racing like this. (This is strange. Definitely strange.) "Then, I'll be going." 北沢泰輔(きたざわ たいすけ) turned toward her and said that quietly. "[gentle]Yes. Please take care." With just that, 北沢泰輔(きたざわ たいすけ) started running again. The regular sound of his footsteps gradually faded into the distance. 紗彩(さあや) found herself watching his back until it disappeared from sight. ——Well. Her face was hot. (Why is my face hot?) She started walking quickly along the promenade. The sound of the river. The rustling of leaves. An ordinary evening. Nothing happened. Just happened to meet the teacher and exchanged a few words. (But his voice was soft.) No, no. That was just her imagination. He was tired after running, so his tone was different. That was it. (But that profile.) So what! The teacher has his own time too, of course. He was thinking about something while looking at the river. That's all. What that something was——it had nothing to do with her. Nothing to do——with her? "……Why do I want to ask?" She whispered it to herself and was startled by her own words. She wanted to ask. What was he thinking about. What was he thinking while looking at the river. This person—— (No, no, no, no.) She immediately shut it down. The principal's voice echoed back. "Appropriate distance." Those words from the orientation meeting came back with terrible timing, crystal clear. He was the homeroom teacher. 凛人(りひと)'s homeroom teacher. Nothing more, nothing less. She had to pick 凛人(りひと) up from after-school care at 4:45. She needed to get back soon. 紗彩(さあや) walked quickly along the promenade. The sound of the river gradually faded into the distance. --- They ate dinner. She checked 凛人(りひと)'s homework. While 凛人(りひと) floated a plastic submarine in the bath, she finished the dishes. Just another ordinary night. Nothing had changed. "Hey, Mom." 凛人(りひと) called out while putting on his pajamas. "What?" "Today I got the math problem wrong again. But 北沢泰輔(きたざわ たいすけ) said, 'You don't need to rush.'" "I see." "The teacher doesn't get angry, you know. Even though he looks kind of scary." 凛人(りひと) said just that and burrowed into his futon. His pre-sleep talk was always abrupt. 紗彩(さあや) turned off the bedside lamp and said, "Good night." 凛人(りひと) answered, "Mm." She returned to the living room and sat down on the sofa. It was quiet. From the south-facing balcony, she could see the night sky in the direction of the river. Almost no stars were visible. The city lights faintly illuminated the sky. (Where is 北沢泰輔(きたざわ たいすけ) right now?) The thought came unbidden. Minami-Nagi district. Beyond the Nishina River. That person's apartment with its unusually numerous bookshelves, as she'd heard mentioned. Fragments of information like that occasionally mixed into 凛人(りひと)'s stories. That profile by the riverside bench, staring at the water. What had he been looking at——? (I'm interested in this person.) She admitted it honestly. But what did that change. Being interested and being able to do something about it were completely different things. A homeroom teacher and a guardian. Any relationship beyond that—— (Besides, he probably doesn't think anything of me.) When that realization hit, something inside her went cold. Of course. 北沢泰輔(きたざわ たいすけ) saw twenty-eight children every day and interacted with their guardians. 紗彩(さあや) was one of them. The observation notes, the parent-teacher conferences——he probably did all of that for everyone. 凛人(りひと) had said, "The teacher doesn't get angry." "He told me not to rush." He probably said the same things to other children. (That's fine.) 紗彩(さあや) stared out at the balcony. Scattered lights floated in the direction of the river. The wind had picked up a bit, and she heard the sound of a planter on the edge of the balcony swaying. "What is this?" She whispered it to no one in particular, very softly. She was still avoiding giving a name to this feeling. If she named it, she felt like there would be no taking it back. Since the divorce five years ago, she had never felt this way about anyone. She had become timid. Afraid of being hurt. And now, like this—— She let out a deep sigh. The sound of the river couldn't be heard. But in the silence of the night, that profile alone refused to fade away.