After a failed love confession, high school student Mikoto Ochiai contemplates jumping off the school building's roof. However, her plans are interrupted by Jin Haiba, the laid-back physics teacher often mocked by students. Instead of talking her out of it, he calmly lights a cigarette and proposes an unusual deal - a romantic relationship before her demise. As they explore the reasons for living and loving, Mikoto and Jin embark on a journey of self-discovery and contemplation.