Chivalry's Lament (2018)

1st film of the 任侠哀歌 series. Kurosaki Ken (Namioka Kazuki), the son of Saijo Fund executive Kurosaki Hiroshi (Akai Hidekazu), gets caught up in a dispute between the Sagawa and Kawashima groups, both of which are affiliated with the yakuza organization Kiryu-kai, and is captured by the Sagawa gang along with his friends Ando Tatsuya (Kitadai Takashi) and Hanamaki Daisuke (Isaka Tatsuya). Just as they are about to be killed, Ken's father Hiroshi saves the three. After being persuaded by Hiroshi, the three swear to reform, but Tatsuya is tricked by Mikitani of the Kawashima gang and is nearly killed. Ken accidentally shoots Mikitani while trying to stop him, and is arrested and sentenced to 5 years for attempted murder. While in custody, his father appears to commits suicide and Ken becomes consumed with guilt and doubts about the veracity of his father's murder. Five years later, Ken is released, and begins to look for answers ...