After killing his daughter’s abusive yakuza boyfriend to save her, ordinary salaryman Tetsuo Tosu becomes embroiled in the dark criminal underworld. The wish for a simple life he and his wife Kasen had for their daughter has been reduced to a wish for survival. Though middle-aged and weak, he’ll put his life on the line using only his wits in order to protect his family.
(Source: Crunchyroll)
— Description from AniList community (anilist.co).
