"Alright, lovebirds," Kenta said, leaning over their table with a grin. "What's your pitch for today? Don't tell me you're just fixing CSS bugs."
"I was planning on building a prototype of the Family Module," Makoto said, pulling up a wireframe on his screen. "Not just a girlfriend simulator, but a family simulation."
Yui leaned in, her eyes bright behind her glasses. "Do you mean multiple waifus? In the same chat?"
"Exactly," Makoto nodded. "The current engine treats every relationship as a one-on-one. But the Family Module will create a shared space. The AI waifus can manage the user's calendar together, remind each other to eat, and argue over who gets to wake him up in the morning."
Makoto continued. "Think of it like this. The old version was a linear visual novel. Our new version is a life-management dating sim where the characters actually care whether you eat breakfast. The hook is that they work together: The Tsundere might nag you about work while the Yandere locks your browser so you don't procrastinate."
Kenta whistled. "You mean a Harem module? That's actually revolutionary for this market, Makoto-kun. Most competitors have the AI waifus act isolated without knowing others' existence."
"That's the challenge," Makoto said. "We need to make them cooperate and feel like a real family, not just a collection of romance routes."
"I love it already, Senpai," Yui said, already pulling up her design tablet. "I'm thinking of a shared household interface, like a calendar where they all leave notes for each other. Maybe one cooks breakfast while another packs the lunch…"
"And they fight over who gets to give the goodnight kiss," Makoto added with a small smile.
===
As the sun set over the Tokyo skyline, the hackathon entered its Deep Work phase. The room dimmed, the only light coming from the blue glow of monitors.
Yui leaned closer to Makoto to look at a line of code. "Oh, that's a clever way to handle the double animation when they're nagging together," she whispered while her shoulder brushed against his. "You're really good at this, senpai."
Makoto flinched slightly, pulling his arm back. "It's just standard logic, Yui."
"You're always so modest, Reliable-senpai," she giggled, reaching out to touch his arm. It was just a fleeting touch, but it felt like a brand. "You smell nice, by the way. Like citrus. Is that a new cologne?"
Back at the apartment, the Wives Command Center was in full operation. The living room was dark, save for the glow of Mika's large tablet. The four wives were huddled around it, their faces illuminated by a flickering waveform of real-time audio feed from Makoto's phone.
Mika sat in the center, wearing her glasses, her fingers hovering over the screen. Yuna sat to her right, holding a sharp paring knife and a bowl of apples. Nobody was eating the apples. Yuna was just meticulously, almost violently, slicing them into perfectly identical slivers.
Ayane was pacing the length of the rug, her muscles tense. Mafuyu was curled up in the armchair, knitting a small yellow sock, her needles clicking in a frantic rhythm.
"…You smell nice, by the way. Like… citrus?" The waveform on the tablet spiked as Yui's voice crackled through the speakers.
"THAT BITCH!" Yuna hissed, the knife slicing through an apple skin with a sharp snip. "She's sniffing him! She's literally putting her nose on his territory!"
"She's interested in him," Mika said, her voice tight. She tapped the tablet, enhancing the gain. "Her attempts are clumsy, though."
"I'm going to go down there," Ayane growled, her knuckles cracking. "I'm going to walk into that hotel and pull Makoto away from her claws."
"Sit down, Ayane-chan," Mika commanded, her eyes fixed on the screen. "We should only act if she does something clearly wrong. Think about the trouble you might cause for Makoto, too." Mika tapped the screen, her expression focused. "I can hear keyboards in the background. They're still in a public space for now."
Mafuyu sat on the couch, her hands busy with her knitting, but her needles were clicking a little too fast. "She sounds very nice, very normal," Mafuyu said softly, her eyes fixed on the waveform. "That's what worries me. She sounds like someone who genuinely likes him."
"That's exactly what makes her hard to deal with!" Yuna shouted, pointing the knife at the tablet. "If she were a scheming bitch, it would be easy! But she's trying to be useful and just be his cute kouhai at work!"
Mika leaned back, her fingers tapping a rhythmic beat on the table. "Things get worse after 11 PM," she said. "People get looser when tired. She'll make her move when the coding slows down."
===
At 1:00 AM, the War Room was a graveyard of energy drink cans and pizza crusts. The air was filled with the smell of pepperoni pizza and high-end gin.
Most of the developers were slumped in their chairs or passed out on beanbags. Kenta and Tokuya were snoring loudly in the corner.
Makoto's eyes were stinging. His eyes were bloodshot, his fingers stiff. He'd spent two hours straight optimizing a memory leak, and his brain was starting to feel like a poorly written script.
"Senpai?" Yui was still awake. She was sitting back in her chair, stretching her arms over her head. The movement caused her hoodie to ride up, revealing a sliver of her pale stomach.
"I'm beat," she sighed, her voice husky with exhaustion. "I think I'm losing my mind. Every time I close my eyes, I see buttons and curly braces."
"Me too," Makoto admitted, rubbing his face.
"You know," Yui turned her chair toward him and tucked a strand of hair behind her ear. "We've been working so hard. I think we deserve a real break."
She leaned in, her voice dropping to a shy whisper. "My mother sent me a bottle of expensive sake last week. It's in my room 1204."
Makoto went still. The air in the room felt like it had been sucked out. "Yui, I… I don't think that's a good idea. We have the demo for the Family Module in nine hours."
She looked at him, her gaze lingering on his lips. "I've really, really liked working with you this month, Makoto. You're different from the other guys here. You're kind and reliable."
"It'll help us relax, senpai," she murmured when she placed her hand over his on the desk, her fingers interlacing with his. "Just one glass, and we can look at the UI mockups on the big screen in my room. It's much more private. No one will bother us there."
===
Back at the apartment, the silence was absolute.
The waveform on the tablet was flat, catching only the low hum of the hotel's HVAC system. And then, Yui's invitation whispered through the speakers.
"…My mother sent me a bottle of expensive sake..."
Yuna's knife slipped, cutting deep into the wooden cutting board. She stared at the tablet for a while, then she stood up, her face a pale mask full of killing intent. "THAT'S IT! WE'RE GETTING THE CAR KEYS, AYANE!"
Ayane stopped pacing and looked at the front door, her body coiled like a spring. She grabbed her trench coat. "I'll drive. We can be in Shibuya in thirty minutes if I ignore the red lights."
Mafuyu's knitting fell to the floor, the yellow sock unraveling. A single silent tear traced a path down her cheek.
Mika sat perfectly still, her pink eyes glowing in the dark. She slowly lifted her hand, her finger hovering over the Remote Alarm button, the new feature she installed in the tracking app that would make Makoto's phone emit a loud screech to alert the entire hotel.
"Wait, Yuna," Mika said, trying to suppress the trembling in her voice.
"Wait for what, Mika?!" Yuna shrieked. "She just invited him to her room for sake! That's code for 'I'm going to take your husband'!"
"Just wait! Wait for his answer. Look at the waveform," Mika commanded. The green line on the screen was flat. There was no movement, footsteps, or rustling of clothes.
"Fine! If he says yes, I'm burning his manga collection," Yuna hissed.
"If he says yes, I'm moving out," Mafuyu sobbed.
"If he says yes," Ayane growled, "I'm going to give him a reason to need that medical insurance he just got."
Mika's finger hovered above the red button. "Choose wisely, Makoto-kun," she whispered to the empty air. "The entire household and your life are on the line."
===
In the hotel, Makoto looked at Yui's hand on his. He looked at her cute, expectant face and the invitation in her eyes. He remembered the kindness she'd shown him all month, the faint sensation when he placed the sensor markers on her mo-cap suit over her breasts.
For a split second, a part of his brain, the part that was tired of the shouting and the jealousy and the constant high-wire emotional act of his life, wanted to say yes. To be normal just for one night. To be with a girl who didn't threaten to castrate him or track his GPS.
But then, he felt a weight in his pocket. It was his phone. He didn't know about the surveillance or the War Room. But he remembered the photo on his lock screen.
Makoto pulled the phone out, not to check for messages, but to look at the wallpaper Mika'd changed this morning. That was a photo he'd taken weeks ago, after they went to a family restaurant to celebrate his first salary.
The five of them are in the park. Yuna was scowling but leaning into his side. Ayane was making a goofy face. Mafuyu was smiling with a gentle peace. And Mika was looking at the camera with that calm possessive pride.
He turned to Yui and said, "Yui-san, I..." His voice was steady, lacking the hesitation he'd felt all month.
At the apartment, Mika's finger twitched. The red light of the alarm button seemed to pulse.
Mafuyu stood up, her hands clasped over her heart, her eyes wide and pleading. "Makoto-kun… please…"
"Darling…" Mika whispered, her breath hitching and her fingers shaking.