In an unremarkable city, at the mouth of a slow, sludgy river, lie an ordinary school and a stretch of undeveloped land where Haruna Wakakusa is struggling to manage her first year of high school. She and her friends are as reckless as they are passionate about romance, and they lack the maturity to handle the consequences—both physical and emotional.

Haruna's classmate, Ichiro Yamada, is a tender young man idolized by his female classmates but brutally bullied by his male peers. After he confides some of his secrets in Haruna, she learns about Yamada's struggles and gains perspective that shapes her relationships with all of her peers. Unable to change the past, and without knowing how their choices will shape the future, Haruna and her schoolmates fumble through their youth, unaware of the disaster that will eventually befall them.