The frantic energy of Sakuragaoka High had dissolved into the slow, syrupy rhythm of summer vacation. The silence in Kaito's room was no longer the quiet of intense focus, but the peaceful quiet of completed tasks. His holiday homework, a substantial packet, sat neatly bound on the corner of his desk, every problem solved, every essay outlined, two days after the break began. The order was satisfying, but it left a vacuum of time he hadn't budgeted for.
Downstairs, the soft murmur of the television and the occasional laugh from his parents were the only sounds. Aiko was home too, her university break aligning with his. He could hear her moving around in her room, the energetic rustle of someone planning something.
His phone buzzed on the desk.
Aiko: Status report.
Kaito: Homework complete.
Aiko: Of course it is. That's not a status, that's a foregone conclusion. I mean your mental status. You're vibrating with unused cognitive energy. It's disturbing the household peace.
Kaito: I am not vibrating.
Aiko: You are. I'm prescribing an intervention. I'm going to the arcade. The new rhythm game cabinet is in. You're coming.
Kaito stared at the message. The arcade. It was a place of loud noises, flashing lights, and chaotic, unproductive movement. The antithesis of his preferred environment.
Kaito: That is an inefficient use of time.
Aiko: It's called 'fun.' You might have heard of it. It's a social experiment. You need data on non-academic human behavior. Consider it fieldwork. Besides, I need someone to carry my prize tickets. Be ready in 30.
He knew arguing with Aiko when she was in this mood was the least efficient action of all. He also looked at his empty schedule. The blank space, usually a comfort, felt oddly hollow. He had no system for unstructured leisure.
Kaito: I will accompany you. I also need to purchase a new novel. My reading list is depleted.
Aiko: A novel! How rebellious. 30 minutes. Don't wear a tie.
As he changed into casual clothes—a simple dark t-shirt and trousers—he considered the novel. It was a practical need. But the arcade… that was Aiko's world. A world of pure, senseless engagement. He had nothing else to do. The reason was as simple and unprecedented as that.
Meanwhile, across town, a different kind of study session was underway. Hikari's holiday homework was a battlefield, and she was losing. Sheets of paper were strewn across the low kotatsu table, covered in her frustrated scrawl and aggressive doodles.
"No, you can't just say the industrial revolution was 'loud and sad,'" Kenji said, rubbing his temples. He was home for the break, playing the role of exasperated tutor. "You need causes. Effects. Dates, maybe one or two."
"But it was loud and sad," Hikari grumbled, stabbing her pencil into the margin. "The dates are boring."
Kenji's phone buzzed. He glanced at it and a grin spread across his face. He typed a quick reply.
Kenji: Change of plans. Rescue mission required. My brain is melting. Taking the little menace to the arcade to burn off her destructive energy. You two should meet us there. New rhythm game.
He showed the screen to Hikari. "Field trip. We're going to go fail at something that doesn't affect your permanent record."
Hikari looked from the chaotic homework to her brother's face. The idea of hitting something, even a virtual drum, held immense appeal. She nodded, pushing the papers away.
Thirty minutes later, Kaito found himself standing under the flashing neon lights of the 'Star Galaxy Arcade,' a novel by a recommended author tucked under his arm. The cacophony was immediate—a symphony of electronic beeps, synthesized music, and the rattle of pinball machines. Aiko bounced on her heels beside him, her eyes already scanning for her target cabinet.
"Okay, ground rules," she said, her voice raised over the din. "No analyzing the probability curves of winning the claw machine. No calculating the optimal trajectory in air hockey. Just… play."
Before Kaito could formulate a response to that illogical request, he saw them. Kenji was weaving through the crowd with easy familiarity, and trailing behind him, looking both disdainful and intrigued by the sensory overload, was Hikari. Their eyes met across a row of racing game pods. A flicker of mutual surprise, then acknowledgment.
Kenji reached them first. "Fancy meeting the honor student in a den of vice," he laughed. "Aiko, right? Kenji. Heard you're the master of the rhythm destroyer."
"That's the one!" Aiko said, beaming. "And you must be the source of the chaotic energy I've been sensing. Perfect. Teams. Me and Kenji versus you two on the new cabinet. Losers buy the winners drinks from the vending machine."
Kaito looked at Hikari. She shrugged, a glint of challenge in her eyes. It was absurd. It was unstructured. It was, he realized with a start, exactly what he had nothing else to do.
"Very well," Kaito said.
What followed was not graceful. Kaito's precision was useless against the flashing arrows and erratic beat. Hikari attacked the buttons with more fury than rhythm. They failed spectacularly, their score a pitiful contrast to Aiko and Kenji's synergistic, laughing mastery.
As Aiko crowed over their victory, Kaito, without a word, went to the vending machine and returned with four cold bottles of green tea. He handed one to Hikari. Their fingers brushed.
"Your timing is mathematically inconsistent," he observed quietly, not as a criticism, but as data.
"Your stiffness is clinically concerning," she shot back, but took the drink.
They wandered the arcade after that. Aiko and Kenji disappeared into a photo booth, striking ridiculous poses. Kaito found a quieter corner with a vintage cabinet puzzle game and began solving it with terrifying efficiency. Hikari found a shooting game, blasting pixelated aliens with single-minded focus.
Later, as they stood outside in the fading summer evening, the neon lights painting their faces in shifting colors, Aiko clutched a small, ridiculous plush toy won from the claw machine. Kenji was teasing Hikari about her alien-killing form.
"You've got the aggression down," he laughed, "but your aim is that of a stormtrooper with a migraine."
Hikari swatted at his arm, but she was smiling—a real, unguarded smile as she stole the won plush from Aiko's grasp.
As the laughter settled, Kenji's expression softened into something more thoughtful. He shoved his hands in his pockets and glanced between Kaito and Aiko. "Hey, since we're all on break and clearly have nothing better to do than waste money on flashing lights…" He nudged Hikari gently with his elbow. "This one's birthday is in five days. We're just doing a small thing at the house. Nothing fancy. You two should come."
Aiko's face lit up immediately. "A birthday? Yes! Absolutely! I'll bring cake. No, I'll make a cake. What kind do you like, Hikari? Chocolate? Fruit? Something weird and artsy?"
Hikari looked momentarily stunned, her eyes darting from her brother's expectant face to Aiko's enthusiastic one, before finally landing cautiously on Kaito. The idea of a birthday gathering, of people in her space for a non-academic reason, clearly sent her internal defenses into a scramble.
Kaito, meanwhile, processed the invitation with his usual calm. A social gathering at the Tanaka residence. A defined event. It was a new variable, but not an unwelcome one. It fell under the expanding category of "things involving Hikari." He gave a small, definitive nod. "I will attend. Thank you for the invitation."
Hikari, seeing Kaito's easy acceptance, seemed to relax a fraction. She gave a tiny, almost imperceptible shrug towards Aiko. "…Chocolate is fine."
"Chocolate it is!" Aiko declared, as if she'd just won another prize. "It'll be legendary. No store-bought nonsense."
Kenji grinned, looking relieved and genuinely happy. "Great. It's settled then." He glanced at his sister, his eyes warm. "See? Told you it wouldn't be painful."
Kaito adjusted the novel under his arm. The arcade had been inefficient, loud, and offered no measurable return on his time investment. And now his schedule had a new, non-academic entry: Birthday Gathering. Chocolate cake.
And yet, as he watched Hikari's faint, reluctant smile return and felt the simple, forward-looking anticipation in the group, he understood something. Some data could not be quantified in notebooks or schedules. It existed in the shared, pointless joy of a failed game, in the cool bottle of tea after, in the quiet acceptance of an invitation, and in the quiet companionship of walking home under a summer sky with the faint, echoing sounds of an arcade—and now, the soft promise of a birthday—fading behind them.
(End of Chapter 24)