Set in the neon-drenched underworld of 1960s Shinjuku, the manga follows two drifters who collide at a boxing gym and are dragged into a violent struggle for survival and purpose. Shinjuku Shinji, a hot-tempered young man with a talent for brawling, joins the Nioh Boxing Gym after seeing a poster in a coffee shop. There he meets Araki Shigeru, a quiet, unremarkable-looking man who goes by the nickname Barikan and possesses devastating fighting ability. Despite their contrasting personalities, the two form a tense partnership and begin training under the gym’s veteran coach. Their path soon intersects with the local yakuza, led by the suicidal son of a crime boss, and a secretive suicide club that draws in both gangsters and ordinary citizens. As Shinji and Barikan climb the boxing ranks, they become entangled in turf wars, personal grudges, and the desperate lives of the city’s outcasts. The story spins through brutal street fights, ring matches, and the decaying glamour of New Shinjuku, exploring themes of loneliness, violence, and the fleeting hope found in human connection. The manga adapts Shūji Terayama’s original novel into a loose, action-oriented narrative, injecting new characters and a distinct 1960s atmosphere. With each passing bout, the two protagonists confront their own demons and the harsh reality that the wilderness of the city offers no easy escape.