Tetsu Takemoto runs a horumonyaki restaurant in Osaka but frequently neglects it due to gambling and unemployment. He lives with his daughter Chie in a working-class district, deceiving his own parents for loan money which he loses gambling. This behavior strains his relationship with Chie, who confronts his selfishness and unreliability.

He maintains a contentious relationship with his ex-wife, Yoshie, who left because of his irresponsibility. Tetsu reacts with hostility upon discovering Chie's secret meetings with Yoshie, seeing them as rejection. Through interventions by family and former acquaintances, including his ex-homeroom teacher's son, Tetsu and Yoshie tentatively reconcile. They spend a day at an amusement park where their relationship begins to rekindle despite lingering tensions.

His interactions with local yakuza boss Shachou define him further. After Shachou's cat Antonio is injured fighting Chie's cat Kotetsu, Shachou converts his gambling house into an okonomiyaki restaurant and hires Tetsu as a security guard. Tetsu frequently complains about Kotetsu's aggression, inadvertently drawing Antonio Jr. (seeking revenge) to their establishment; the situation de-escalates peacefully due to Kotetsu.

Tetsu consistently speaks in the Osaka dialect. His character shows minor development, briefly stabilizing his work and reconciling with Yoshie, yet his core traits of financial dependency and avoidance persist. In later media, his role remains largely unchanged, exhibiting the same behavioral patterns.