Second-year high school student Konno Mizuki belongs to the main clique in her class led by Himesawa Sakura and knows how to get things done. However, she does not even take notice of the classmates outside of her clique. One morning, Mizuki’s class sets off in a bus for a camp to promote interaction.
The bus which should be headed to Yamanashi races towards Shizuoka, and when a puzzled Kamiya Chieko looks at the driver, she notices that he has stopped breathing. In the next instant, the bus tilts greatly. Then it plunges off a cliff in the mountains. This incident will be the catalyst for a drastic change in the students’ fates. Mizuki regains consciousness inside the bus, and sees that many of her classmates are dead.
Only five including Mizuki have survived the accident but are stranded at the bottom of the cliff. When no one comes to their rescue, raw emotions come to the fore in the face of this extreme situation and their daily power relationship breaks down. Instead of cooperating with each other, the five of them start a fight for survival.