Director Park Jin-pyo, behind the 2005 romance movie “You Are My Sunshine,” has returned with a delightful comic action hero flick that shows a straightforward tale of a high school teacher seeking vengeance on a school bully.

In Park's "Brave Citizen," substitute civic education teacher So Si-min (Shin Hae-sun) silently endures exploitation, having to grade test paper of her peers, and sexual harassment by the vice principal, for the sole purpose of making it as a full-time teacher.

When she notices student Han Soo-gang (Lee Jun-young), dubbed "crazy dog" for his bullying antics, constantly beating up not so well-off students, she -- a hidden boxing enthusiast -- almost can't help but punish him. She barely holds herself back, thinking about her job that is on the line.

But as Soo-gang continues to do evil even outside school, So decides to take the matter into her own hands, putting on a cat mask to avenge the powerless students.

Based on the webtoon of the same title, "Brave Citizen" rapidly unfolds the mercilessness of Soo-gang, who is not afraid of anyone and bullies others just for his own joy. The plot is simple and straightforward, showing how a clearly good-hearted protagonist takes down an evil antagonist through satisfying action scenes.

The industry’s most renowned action master and movie director, Heo Myeong-haeng, behind “The Roundup” series and “Hunt” (2022), choreographed the action sequences of this film. The scenes offer the audience catharsis just by watching the hard-boiled heroine throw punches and smash roundhouse kicks. It’s almost hard to believe that it’s Shin Hae-sun’s debut action film.

Actor Lee Jun-young's intense stares and gruff voice as the villain has taken it up a notch, compared to his previous bad-guy roles in the Netflix hit series “D.P.” and “Mask Girl.”

The film's themes that deal with timely social issues such as school violence and infringement of teachers’ rights also offers an immersive, relatable story line for the audience.

Director Park told reporters after the press film screening held in Seoul on Oct. 18 that he worked on the scenario 2 1/2 years ago and didn’t expect the main topics of his film to have grown into such a sensitive issue.

“School violence and teachers’ rights issues are something that have been going on from long ago. It was just something not well known to many people, or many people would just shun it. Now, those issues are becoming more exposed to the world,” he said, adding that he hopes the audience would feel a sense of lightness and relief after watching the film.

But Park’s buildup in showing Soo-gang’s merciless bullying on his school friends can be hard to stomach. Scenes such as Soo-gang putting a plastic bag on a friend’s face, and more gory moments, fill up more than half the film time.

“Brave Citizens” hits theaters on Oct. 25.