In a Tokyo office building, three former Detective Club members find themselves brought together for some unknown reason: Shota, Chris, and Kazuki. Before they can even celebrate their reunion, they're suddenly caught up in a locked-room confinement incident! Chaos erupts as they question “Huh? Why us?” “Who's the culprit?” Chaotic conversations in English and Thai fly around, mysterious messages are sent, and even their “dark pasts” from elementary school is exposed, pushing them to the brink of panic. Suspicion and sarcastic remarks never stop! Friendship? Betrayal? Or just a misunderstanding? Amidst the chaos, the three confront their past selves and inch closer to the truth behind the incident...