If human primal desires are nothing more than chemical impulses, then what meaning is left in our existence? And in the end, where are we even headed?
Lying in bed, that question lingered in Haruto's mind like a shadow. He didn't want to move, not even lift a finger. His gaze remained fixed on the dimming sky outside the window, where the last traces of sunset slowly bled into a vast, starless night. Through the dying light, he felt as if he could glimpse into the boundless void of the universe, searching for some hidden truth behind its existence.
The room was filled with the quiet rustling of clothes. Setsuna tugged her skirt back into place, while Sekai awkwardly tried to cover herself with one hand, retrieving her shirt from the edge of the bed and slipping it on with practiced, almost mechanical movements. Yet, her gaze kept drifting toward Haruto, still sprawled out on the bed, unmoving.
"You're not getting up?" she asked, glancing down at him with a mixture of concern and awkwardness.
He turned his head slightly, his eyes hollow as they traced the contours of the ceiling.
"Just... a bit longer. I need to rest a bit more."
Five minutes earlier, Mai had returned home and called out from outside Setsuna's room, asking if the three of them were in.
If she had come back even a little later, Haruto honestly wasn't sure if he could've lasted much longer. Two hours locked in that room had drained him more than he expected. While he'd held up fine during the act, now that it was over, it felt like his body was completely hollowed out—no strength left to even twitch.
Setsuna, now fully dressed, gave him one last glance before quietly walking over to the door and slipping out of the room. Sekai, meanwhile, was still fumbling with her bra, both arms twisted behind her back, struggling like it was some kind of puzzle.
But Haruto simply stared, unmoving. His eyes, strangely clear and empty, fixated on her as if seeing right through her.
Sekai paused mid-motion, catching that gaze. A flicker of unease crossed her face, and she instinctively averted her eyes.
"I'll head out too… You figure out when to get up," she murmured, slipping on her jacket and hastily exiting the room.
Alone now, Haruto remained flat on the bed, staring blankly at the ceiling. He didn't move.
In the hallway, Mai had just returned from work. As Setsuna exited her room, Mai's eyes narrowed slightly at the sight of her daughter's disheveled hair—clearly unbrushed. She stared at Setsuna's face for a long moment, silent but probing.
"...Something wrong?" Setsuna asked, calm as always.
"You were in the room with Haruto?"
"And Sekai."
"...All three of you?"
"Mm-hmm."
Mai's mind stalled. She couldn't fathom her daughter's logic. What kind of girl could willingly share the person she liked with someone else? The generation gap between them had never felt wider.
Then again, Mai thought bitterly, wasn't she sharing as well?
She sighed, her eyes drifting toward the closed door of Setsuna's room.
"You left the room… Are you okay leaving the other two alone?"
Before Setsuna could reply, Sekai stepped out of the room as well. Their eyes met. Sekai stiffened immediately, her face tinged with guilt. She offered a stiff little nod and a soft greeting.
"Good afternoon."
Mai stared at the girl for a moment, then gave a small nod in return. Something about the whole situation gave her an odd sense of déjà vu.
She turned her gaze back to Setsuna, debating what to say but unable to find the right words. After a pause, she sighed again.
"Anything you'd like for dinner tonight? I've got time—can head out to pick up ingredients."
"Anything's fine… but preferably something nutritious. We kind of need it."
"Huh?"
Mai looked puzzled for a second. But when she followed Setsuna's line of sight toward her bedroom, a flash of understanding passed through her expression.
What did they get up to in there?
She didn't ask further. There would be time to corner Haruto about it later. For now, she grabbed her bag and headed back out to restock the fridge.
With Mai gone, it was just Setsuna and Sekai left in the room. Sekai sat awkwardly in the living room, debating whether or not to peek back into Setsuna's room to check on Haruto. But the thought of facing him again after that was too embarrassing. So she just quietly sat down and stared at nothing.
Back in Setsuna's room, Haruto finally pushed himself up.
The sky outside had turned to complete darkness. He reached for his clothes without a word, slipping each piece on slowly, deliberately.
He wasn't entirely exhausted. Not physically, at least. But his mind was a blank slate. He didn't feel like doing anything.
Fully dressed now, he cast a glance toward the door. Then, with slow steps, he made his way out into the living room.
Mai and Setsuna were both there—busy preparing dinner.
"Where's Sekai?" He asked.
"Just left," Setsuna replied, not looking up from the vegetables she was slicing.
"I see... then I'll just sit for a bit."
Mai looked up at him from the kitchen. She couldn't help but notice how light-footed he was, almost like he was floating. And somehow, she felt a little... disappointed?
Had she missed the moment?
Chiding herself for thinking such things, Mai returned to the stove.
An hour passed. Dinner was ready.
Sitting at the table, Haruto looked down at the array of nutritious dishes and couldn't help but feel something was off. He glanced toward Mai—she met his eyes with a gentle, knowing smile. Then he turned to Setsuna, who remained silent. Without a word, he picked up his spoon and drank a mouthful of chicken soup.
After the meal, Setsuna volunteered to clean up. He slouched on the sofa, idly poking cut fruit with a toothpick and watching whatever was on TV.
The calm didn't last.
Mai finished her kitchen duties and slowly made her way to the couch, sitting beside him.
"Tomorrow's the weekend. Got plans?"
He looked up. Setsuna had just headed off to the bathroom for a shower, leaving the two of them alone.
His instincts screamed that he might be in trouble. Not that he was completely out of energy… but still, the situation felt dangerously precarious. He sat stiffly, watching as Mai leaned in just slightly, her mature figure subtly brushing against his side.
"We could go somewhere nearby," he suggested carefully.
"Feeling tired?"
Her tone was teasing, but her hand landed boldly on his thigh.
Haruto turned to look at her. Wasn't he supposed to be the guy here?
He had no idea what Setsuna might have told her mother, but he was sure the older woman already knew what had happened in that room. Her question wasn't really about physical fatigue—it was that kind of tired.
But even if a man was drained to his core, how could he ever admit defeat at a time like this?
"I'll be fine after a bit of rest."
"Young people really do recover fast," Mai said, her voice warm and teasing. "So... how about staying over tonight?"
Looking at Mai, who was already clinging to him, her arms wrapped around his waist, her intent clear in her eyes, Haruto opened his mouth, thinking he should refuse. But those eyes—mature yet gleaming with childlike hope—made the words die in his throat.
Just as Setsuna stepped out of the bathroom, Haruto was being pulled into Mai's bedroom.
Their eyes met for a fleeting moment—he didn't even get a chance to say anything to Setsuna before the door shut behind him.
Alone in the living room, Setsuna stood still for a while, staring quietly at Mai's bedroom door.
Then she turned, walked over to the fridge, and took out a bottle of milk. Lowering her gaze, she looked at her own chest—flat enough to see the tips of her toes with ease.
Without a word, she twisted off the cap and took a long drink. Then she walked back to the living room, turned on the TV, and sat silently on the sofa. The sound of faint, muffled moans occasionally filtered through the walls—like a quiet echo of the humming she had done earlier that afternoon.
Glancing once more at her mother's door, Setsuna quietly turned her head back and chose to ignore the sounds, simply watching television in silence.
It wasn't until 10 p.m. that everything finally settled down.
Exhausted, Setsuna left the living room and returned to her own room. She opened the door, climbed into bed, and shut her eyes.
Haruto, meanwhile, lay next to the sleeping Mai, wide awake. Sleep wouldn't come to him—his mind was far too restless.
He remained there in the dark for a while, listening to Mai's steady breathing. Then, gently pulling back the blanket, he slipped out of bed, quietly padded to the door, and opened it with care.
He looked back at the sleeping woman one last time… and then stepped out, closing the door behind him.
In the silence of the room, Mai clutched the blanket to her chest. A soft sigh floated through the empty air.
Haruto crept into Setsuna's room. Bathed in moonlight, the girl was already asleep, her form curled up on the bed.
He moved slowly, carefully lowering himself beside her and slipping under the covers. The girl stirred, sensing the shift. She turned gently, her eyes fluttering open.
Seeing his face in the dim light, Setsuna blinked.
"…Mom?"
She whispered the word, her voice barely audible—strangely small and cautious, even though she was in her own room.
"She's asleep," he murmured back. "Probably."
He had the feeling Setsuna hadn't really been asleep at all.
"Hold me," she said.
He reached out, wrapping his arms around her, pulling her small frame into his chest. Neither of them spoke another word.
They just held each other in silence… and slowly, they drifted off to sleep.
It was the weekend, and just as planned, they went out together.
The three of them made their way to Kasai Sea life Aquarium by Tokyo Bay. The total cost for the tickets was 1,650 yen—Haruto and Mai paid 700 yen each as adults, while Setsuna, only fifteen, got the youth ticket for 250 yen.
"So sixteen counts as an adult, huh…"
Haruto glanced at his ticket, then turned to look at Setsuna beside him, who was holding her youth pass with a conflicted expression on her face. A soft chuckle escaped his lips.
"Well, you can get married at sixteen here. You'll be an adult too, next year," he said.
Mai noticed her daughter's silent sulking but didn't take it too seriously. She offered a casual reassurance, and with that, the three of them stepped into the aquarium together.
Meanwhile, at home, Sekai lay sprawled across her bed, staring blankly at the ceiling. The realization that she'd be alone all day while Haruto was out with Setsuna and her mother filled her chest with an unbearable emptiness. It was as if a part of her had gone missing—and she didn't even know what to do with herself anymore.
"Mom's working today too… even on weekends. She still has to run the restaurant…"
From as far back as she could remember, her mother, Yoko Saionji, never really had much time for her. Holidays were just… days she spent alone.
If she had asked yesterday—just once—maybe she could've tagged along with Haruto and the others.
But now…
Sekai turned over again, clutching the blanket in her arms, her body tense and restless. The frustration and loneliness gnawed at her, making it hard to breathe.
Back at the aquarium, the three of them spent nearly the entire day wandering through exhibits—arriving around ten in the morning and finally leaving close to two in the afternoon. Afterward, they headed to a restaurant in Minato City. Haruto accompanied the mother-daughter pair through a round of window shopping, and as evening approached, they sat down to eat at a well-known local spot.
"Seems like I've still got it, huh?" Mai said with a smirk, settling into her seat at the table.
She had just returned from the restroom, where a man had clearly tried to flirt with her. It wasn't far from where they were sitting, and Haruto had witnessed the whole thing.
"I've always known you're charming, Mai-san," Haruto replied with a calm smile.
Setsuna shot him a glance from the side.
"You too, Setsuna. You're really cute," he added, shifting his gaze to her.
Mai chuckled softly. She was nearly twice his age, and yet the way he spoke made her heart flutter. The look in her eyes was filled with affection—but when she turned to glance at her daughter, there was something else there too: pride… and a flicker of guilt she couldn't quite hide.
That night, after walking the Kiyoura women back home, he began the slow walk to his own apartment. As he reached his doorstep, something caught his eye.
There was something lying on the floor in front of his door.
As he stepped closer and got a clearer look, Haruto's expression shifted into one of sheer astonishment.