Season 1

Inspector Na Hwa-jin steps into the chaos and takes control of a school plagued by the spoiled son of a powerful politician — to teach him a lesson.

With unassuming Bong Geun-dae on his side, Hwa-jin uses his special ops skills to handle a school gang and defend a student who just wants to study.

When a teen influencer spreads false claims about her teachers, the team's loose-cannon Inspector Im Han-rim steps in to set the record straight.

Choi Gang-seok weathers a political attack on his bureau. Hwa-jin's team visits an elite school to uncover why a student attacked a respected teacher.

When an elementary school teacher's spirit wears down under pressure, Hwa-jin steps in to be her substitute — turning the tables to solve the case.

Four juvenile delinquents think they're above the law — until the team takes an interest in their extracurricular crimes and gives a harsh reality check.

Geun-dae goes undercover to help a father find his gambling addict son. To undermine the bureau politically, Hwang Gi-tae visits a juvenile inmate.

After a pre-med student collapses in class, Hwa-jin investigates his obsessive mother, whose access to illicit pills hints at a larger conspiracy.

To help a student escape his exploitative friends, Han-rim adopts a new persona to join his circle. Cho Gyu-cheol's return puts the bureau in danger.

After public backlash hits the bureau, Hwa-jin and his team go rogue to expose a deadly conspiracy led by a violent student-run gang.