Jinsei Nagai, also known as "Bare-Knuckles Jinsei," was born in a dumpster, raised in an orphanage, and lives as a yakuza. He is tough enough to fight all his battles bare-handed and is covered in countless knife and bullet scars. However, his life changes when he saves five-year-old Ayumi, the daughter of the new police chief, Masayoshi Enjouji, and befriends their family. For the first time in his life, Jinsei feels as though he has found a family of his own and decides to start over, but his past and his ties to the yakuza continue to get in the way.