In a world where your future is judged by computers. A young boy, Yuhi Touji, was judged to be a "sinner of tomorrow" who will commit a crime in the future, and he was sent to an rehabilitation program on the uninhabited Tetsumado Island, where 12 "Tomorrow's Sinners" were gathered together. They had only one mission, to prove their innocence through a year of living together. However, over time, the darkness that lurked in their hearts of gradually began to be revealed. ......? The twists and turns will lead to redemption? Or is it despair? Let the "special lesson" begin! (Source: Dengeki Bunko, translated)