Jun-ho is the younger brother of In-ho. Both brothers became police officers until In-ho participated in, and won, the 28th Squid Game. By 2020, In-ho had gone missing, and Jun-ho began his search to find his brother

Jun-ho overhears Seong Gi-hun at the police station trying to tell the police about the Squid Game. The police doesn't take him seriously, so Gi-hun angrily exits the police station and leaves the Squid Game's business card behind. Jun-Ho recognizes the card