During Summer Break, a high school student named Gerard was afflicted with a mysterious device. He named this device the Death Clock, as it's a clock that counts down the remaining days he has left. With the 3rd year of high school starting, Gerard has become disillusioned and ready to just let the days go by. It wasn't until he meets Agatha during the first day of classes when his entire plan goes upside down. Agatha is a mysterious transfer student, and the two began a strange relationship, which starts and ends with the Death Clock.