One Room of Happiness summary: The police are mobilizing to find a 14-year-old girl who has disappeared. Her parents, who are worried sick, fear that she is in pain and suffering. But that is not the case, for she has willingly fled to live with her kidnapper, a former stalker, who she affectionately calls "Oniisan". She has no intention of returning to her abusive parents or school, where she was mercilessly bullied. As time passes, their connection deepens, and she asks for a new name, "Sachi". Despite understanding their relationship is far from ordinary, they vow to marry if they escape from the police and Sachi's parents, or perish trying. Holding on tight to the tiny bit of genuine happiness they've discovered in one another, the twosome cling onto their only chance of hope in a harsh world.