AKUTSU Minoru (KOBAYASHI Kaoru present self, TOZUKA Junki past self), serving a life sentence, awaits a lonely death in his prison cell. The only real sign of life in the cell is a potted balsam flower — hosenka in Japanese. One night, Minoru begins sharing his life story with the flower that, improbably, talks back — prompting him to reflect on the meaning of life.

The summer of 1987. Minoru, a low-ranking yakuza member, lives with single mother NAGATA Nana (MIYAZAKI Yoshiko present self, MITSUSHIMA Hikari past self) and her son Kensuke (HANAE Natsuki). Despite being shy about expressing his feelings, Minoru loves them with all his heart.

However, when Minoru suddenly faces a desperate situation and needs a large sum of money, he teams up with TSUTSUMI (YASUMOTO Hiroki), a senior gangster, to steal 300 million yen from their gang’s safe. Caught in a web of misplaced loyalty and friendship, Minoru finds himself manipulated but still clings to the hope of one last secret comeback from his troubled life.