On June 2 at eight in the morning, the Advanced Nurturing High School gymnasium hosted the briefing for the first-stage cross-class collaboration task. A row of long tables had been set up temporarily on the basketball court, with Chabashira-sensei, the second-year Disciplinary Committee Chairman, and Sakagami-sensei seated behind them. Sakagami-sensei's appearance made the atmosphere in the gym feel strange. The gray-haired retired teacher had stopped teaching classes at the end of last term and only appeared occasionally in the Library and the archives. Yet today, he sat at the center of the panel, an old, yellowed Old System record spread out before him and a cup of unsweetened black tea at his side. When Shiina Hiyori entered the gym, Sakagami looked up at her and gave her a slight nod. It was so subtle that only Kanzaki Toru, seated beside Shiina, noticed. He remembered the pencil note Sakagami had left in the margins of the Old System archives: "Pay attention to whoever took this photo." The photo's composition was identical to countless shots of the high wall Sakura Airi had taken from the rooftop.
"The details of the first-stage cross-class collaboration task have been sent to your devices." Chabashira-sensei stood, dispensing with any unnecessary opening remarks. "This task is the Uninhabited Island Survival Exercise. Each group will undergo five days of wilderness survival training on an uninhabited island under the school's jurisdiction and complete the assigned collaborative challenges according to the requirements. The island has safety monitoring stations and emergency evacuation routes. All activities will be recorded in real time and factored into your collaboration scores."
Uninhabited island. The words fell beneath the gym's vast dome like a pebble dropped into deep water, sending ripples across each face at a different pace. Ken Sudō's eyes lit up—not with the ferocious glint he got before a fight, but with the excitement of finally getting to do something he was good at. Kanji Ike muttered, "We're going to get eaten alive by mosquitoes again," and Sudō threw an arm around his shoulders and shook him twice. At the back of Class C's section, Ishizaki Daichi studied the equipment list on his device, his finger tracing the "first-aid kit" entry again and again. The palm he'd cut while climbing the Old School Building's outer wall still hadn't fully healed, but now he wasn't thinking about his old injury. It was that familiar item on the list that caught his attention. Shiina Hiyori quickly searched the Library database for borrowing records of every book on wilderness survival and noted the name of her Class B groupmate, Hamaguchi Tetsuya, in her memo. Last term, Hamaguchi had helped the Basketball Club put together a fitness program, so he was no stranger to outdoor activities.
Karuizawa Kei stood beside Group 8's assembly point, holding the portable mosquito repellent patch Sakura Airi had given her that morning. She opened the package, stuck one patch to the back of her hand, then quietly slipped the rest into the gear bag of the Class C girl in her group. After Sakura had told her on the rooftop not to put up her guard, she'd decided to try approaching people more casually during this exam.
"Group 12: Kanzaki Toru, Shiina Hiyori, Hamaguchi Tetsuya, Ishizaki Daichi, Morishita Ran, and Nomura Takuya. Meeting point: left side of the basketball court." As Kanzaki Toru headed for the meeting point, Ishizaki had already taken up a position half a step behind him. Unlike the night at the Old School Building, when he'd left his uniform collar open, ready to take or throw a punch, he now stood quietly with the kind of unspoken understanding found on a sports team. Hamaguchi Tetsuya ran over from the Class B section with an equipment bag, slipped a box of waterproof matches into the shared backpack, patted Ishizaki on the shoulder, and waved to Morishita Ran and Nomura Takuya.
After the briefing, the groups boarded their boats one by one. Four small ferries waited at the pier, each bound for one of the island's four landing points. A sea breeze carrying a faint, briny smell drifted in from beyond the high wall. Sakura Airi stood at the pier and glanced back at the gray-white wall behind her. When she'd first set up her tripod on the rooftop last term, she'd pointed her lens in this direction. Back then, she hadn't been sure what she wanted to see through the viewfinder. Maybe she'd just been waiting for some nonexistent signal. But today, she knew she'd keep pressing the shutter on the island. Not to collect evidence, but to document things. To document Ishizaki handing the first bottle of water to Morishita Ran when Group 12 divided their supplies; Karuizawa sticking a mosquito patch to her fingertip and pretending it was a new nail; Kanzaki turning his head during their group discussion so the sunlight fell right in someone else's line of sight. She opened her phone. While they'd been sorting their gear the previous night, Karuizawa had sent her a message, just one line: "You don't have to photograph me, but if you get a shot of that Class C girl in our group, could you ask her—which would she pick as a must-have for five days on the island, wet wipes or candy?"
Sakura hadn't replied, but she'd saved a screenshot of the message to her album. Now she walked a few steps behind Karuizawa, her cap brim still pulled low, but her steps steadier than ever before.
The independent task group's notice arrived at the same time. Ryuen Kakeru stood at an observation point on the other side of the pier, holding an observation log and a yellowed record of the Shared Pool Allocation. As an independent observer, he was to sit in on all of the first day's collaboration meetings on the island, submit two observation reports, and complete a literature review on the Shared Pool Allocation within five days. His device still displayed footage Ishizaki had sent the previous night, along with a voice message he hadn't answered. Ishizaki had said, "Next time you need to climb a wall to look something up, bring me along." Ryuen hadn't replied then, but now he typed three words—"Get on board." Then he deleted them and put his phone away.
The engines of all four ferries started almost at once, their propellers churning the gray-blue water. Twelve collaboration groups and one independent observer set off together toward the uninhabited island beyond the high wall, half-veiled in sea mist. Even after everyone had boarded, Sakagami-sensei remained seated in a corner of the gym's review panel. He turned to the page of the record's timeline showing the signature dates on rejected cross-class reports, then back to the old photo's composition from the same angle. He closed the file and picked up his cup of tea, now gone cold. Morning sunlight divided the gymnasium's skylight into a clean diamond of light, which fell squarely on the empty basketball court.
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