Seri Agawa commands the criminal organization 831 Front. He is the half-brother of Nazuna Hashimoto, a girl possessing the ability to stop time. After both their parents died, Nazuna lives with Seri in Tokyo as her sole remaining relative.

Seri holds a consuming hatred toward established power structures and vested interests, driving him to orchestrate unprecedented criminal activities through the 831 Front as retaliation. He leverages Nazuna's time-stopping ability to facilitate these crimes, compelling her participation through their familial bond. Nazuna finds herself unable to resist due to her dependence on him as her guardian.

The 831 Front operates with a structured hierarchy. Seri collaborates closely with twin subordinates known as the Sakata brothers, who manage communications fraud and member recruitment. Another key operative is Donki, an emotionless executor who carries out dangerous missions without hesitation.

Seri's criminal actions ignite the central conflict when Suzushiro Asano, another individual with time-stopping abilities, discovers Nazuna's forced involvement. Suzushiro's move to help Nazuna escape places him in direct opposition to Seri and the 831 Front organization.