Mizuki Konno is a high school student. She belongs to the the most powerful group in the class, which is led by Sakura Himezawa, so she can have a peaceful school life. One day, on the way to a school exchange event, a school bus driver becomes unconscious due to overwork. The bus goes off a cliff. Including Sakura Himezawa, a majority of Konno's classmates die in the accident. Only five students including Mizuki Konno, Chieko Kamiya, Haru Ichinose, Arisa Morishige and Chikage Usui survive the accident but are stranded at the bottom of the cliff and no one come to the rescue. Raw emotions come to the fore in the face of this extreme situation. The five scatter instead of sticking together to survive.