Masayoshi Satsuki teaches Life Guidance at Kuzuryū High School and reluctantly accepts the role of basketball club advisor at the principal's request. Residing in Kanagawa Prefecture with his pregnant wife, he initially views the club as a haven for delinquents avoiding basketball. Following an incident where Kenji injured upperclassmen, Satsuki issues a stern warning: any further fighting means immediate club disbandment.

His demeanor transforms as the team shows increasing dedication, especially during practice. Motivated by their efforts, Satsuki begins studying basketball through books to better support them. He witnesses his first official match as advisor during a practice game against Kitasumi High. Though the team loses, their performance impresses him. Recognizing their hard work, he rewards them with a celebratory BBQ dinner as an advance incentive for future victories.

Satsuki's interactions trace his shifting perspective, moving from initial frustration with team conflicts to expressing genuine investment in their progress. After the Kitasumi match, he openly shares his spectator frustration and urges the team to win next time. His guidance emphasizes enduring necessary hardships, reflecting his belief in bearing unavoidable pain. His name, Masayoshi (正義), meaning "correct, justice, righteous," aligns with his role guiding the team toward discipline and structure.