Unless it's a holiday, students only have free time on weekends.
On this rare weekend, Takamine Rinji didn't stay home playing games like usual. Instead, he went to visit the research department—not because he was especially motivated, but because it felt wrong to keep skipping when he was listed as an official advisor.
The last time he came was a week ago—when he buried the currently-MiaKO Ogino In a vacant lot near the lab.
Ever since arriving in Japan, Rinji hadn't properly visited the research department.
"Advisor Takamine, the prototype is ready for testing."
"Oh? Let me take a look."
Inside a massive facility, high-end equipment was everywhere, and white-coated researchers bustled about. Rinji had changed into a lab coat as well. Guided by one of the staff, he entered a specific room.
His official position here was Technical Advisor—the kind that's never actually around.
The room held a large control platform and a mechanical arm in the center. In front of it sat a helmet-like device.
"This thing's been in development for years now, right?"
"It was actually completed in the '90s. The last chief designer made it as a military prototype. But after she left, the focus shifted. Five years ago, HQ decided to adapt some military tech for civilian use, and this project resumed."
"Whether it's commercially viable now depends on marketing…"
Rinji stepped up and put on the helmet.
Once a researcher hit the power switch, the helmet lit up—and the robotic arm began to move, its fingers flexing with surprising dexterity.
It was a prototype for a medical robotic limb—an ongoing research project.
"The responsiveness still needs work. It doesn't feel much better than the commercial muscle-sensor prosthetics."
"Well, the ones on the market haven't even been released yet. And ours can connect directly to the nervous system."
"From a commercial standpoint, I'd still say it's risky. The sensors need major upgrades—it should at least match the dexterity of a real hand. Send me the schematics later."
"Understood."
After taking off the helmet, Rinji turned to ask, "How's progress on that exoskeleton project?"
"Still in testing… and honestly, probably won't sell as a civilian product."
"Figured. I'll report back and recommend we keep it military-only."
Just as he said that, his phone buzzed.
He took it out—someone had messaged him on LINE.
He didn't have many contacts: Aunt Kaya, Shirogane Miyuki, Ishigami Yuu, Ryuju Momo… and the most recent addition, Fujiwara Chika.
Sure enough, it was her.
[Rinji-kun, are you free this afternoon? As per our little wager, let's go on our date today~ Come to Harajuku! Here's the address…]
"…She actually remembered?"
According to the terms set during the board game club incident, in addition to their funding being set to zero, Makihara Kozue had unilaterally decided that Fujiwara Chika would go on a date with him.
Though that decision was made without Chika's input, she surprisingly followed through.
But after spending some time around her, Rinji suspected this 'date' wasn't going to be what he expected.
Still, reality exceeded even his low expectations.
When he arrived by taxi at the meeting spot in Harajuku, he found Chika—dressed in fashionable street clothes—but also another girl.
This girl looked like a younger version of Chika. With twin pink pigtails, she was clearly adorable.
"Rinji-kun, let me introduce you! This is my little sister, Fujiwara Moeha. She's in Shuchiin's middle school."
"Hello, Rinji-senpai."
Moeha gave a polite bow.
"…Hi."
After greeting her, Rinji beckoned Chika over and whispered, eyes narrowing, "So… this so-called 'date' is two girls hanging out with one guy?"
"Of course not~"
"Then why is your sister here? I don't get it."
Chika whistled innocently, avoiding eye contact.
"Come to think of it, Harajuku's full of shops girls love. You two probably planned to go shopping anyway and just dragged me along to carry your bags, didn't you?"
"No way~ I'd never do something so mean."
Chika smiled sweetly.
"We just needed a 'gallant escort,' that's all."
"…So I'm your unpaid bodyguard. Feels like I lost that game of blackjack."
"Geez, you've got three cute girls with you today! That's a rare treat."
"If none of them included you, I might agree. And wait—three? Aren't you and your sister just two?"
"Oh, she should be here soon. You know her too."
"I do?"
Just then, someone came jogging up.
Long silver hair flowing behind her, black lace ribbon on her head, elegant features—Rinji definitely recognized the girl.
"Sorry, Moeha, Chika-senpai, I'm late."
Shirogane Kei bent over, catching her breath, then looked up—surprised to see Rinji.
"Rinji-nii!? What are you doing here?"
"So it's the president's little sister… I didn't know you and Fujiwara were friends."
"Yeah, I'm friends with Moeha, so I got to know Chika-senpai too," Kei explained. "Did Chika-senpai invite you here?"
"Yeah. This evil woman tricked me."
If it had just been the Fujiwara sisters, Rinji would've ditched them without a second thought.
But with Shirogane Kei there—Miyuki's little sister—he couldn't just walk away. If anything happened, it'd be a huge problem.