Sam, a young individual, enlists private detective Hazama Itsuru to find his missing father—a professional football player who vanished under mysterious circumstances. This disappearance ties directly to the theft of cybernetic components from Professor Tani’s laboratory, components illicitly grafted onto athletes and others, triggering violent incidents. Sam’s quest drives Hazama’s initial investigation.

After Hazama transforms into the new 8 Man following a fatal encounter, Sam evolves from client to informal companion, witnessing the detective’s struggle with his dual identity and cybernetic enhancements. Sam’s personal stake deepens when his father surfaces among the cybernetically augmented victims. Driven insane by the "Psycho Serum" essential to operate the enhancements, Sam’s father joins a violent rampage during a football game, indiscriminately attacking spectators.

In the football stadium’s aftermath, Sam observes 8 Man lethally intervene to halt the augmented players, including his father. This prompts Sachiko Yokogawa to confront 8 Man over excessive force. Sam later reunites with his father, who survives but requires rehabilitation to overcome serum dependency and adapt without cybernetics.

Sam’s arc concludes with this reunion, resolving his core motivation. His journey underscores the human cost of the cybernetic crime wave and anchors the narrative’s exploration of technological exploitation.