In the summer of the third year of high school, guided by an answering machine message from the past left on a mobile phone, Sakura Umi meets and falls in love with Harukawa Masahiro, the most problematic child in school. The two quickly shorten the distance, but when the truth of the timeless answering machine is revealed, the shocking past of Umi emerges. Adapted from the novel with the same name by Yukako Kabei.