On the same night that a terminal station in Tokyo experiences a horrific gas terrorist attack that kills and injures a total of 666 people, 31 year-old Kanzaki Hajime coincidentally meets and spends the night with his childhood friend, the now-famous 26-year-old actress Kidō Kotone. Named as the perpetrator, she also dies on the spot. As Hajime starts to investigate the circumstances of the tragedy, he is suddenly killed by someone and time-leaps into the past. As a result, he gives his all to keep her from committing the attack in the “future”…