12 Suicidal Children12-nin no Shinitai Kodomo-tachi; 十二人の死にたい子どもたち; 12 Suicidal Teens; 12인의 죽고 싶은 아이들; Двенадцать детей, которые хотят умереть; 十二个想死的少年; 十二個想死的少年

The story is a locked-room mystery where 12 kids go into an abandoned hospital to give up on life. In the room where they meet, a boy is already lying dead, and no one knows who he is. (Source: ANN)