Yuuichi Katagiri, accustomed to financial struggles, finds solace in his tight-knit circle of friends. Determined to fulfill a promise, he saves diligently for a school trip, only to face a setback when the collected funds vanish mysteriously. Suspicions point to Shiho Sawaragi and Makoto Shibe, despite their innocence. Taking the blame, they shoulder the responsibility. Soon after, the group is lured into individual traps through deceptive letters, awakening in a strange room with