Good people do evil things. When do those actions turn them from good to evil? This is the core question asked in “The Chronicles of Evil,” a new thriller by director Baek Woon-hak.

Actor Son Hyun-joo stars as Choi Chang-sik, a decorated detective who commits a murder in self-defense but covers it up for fear of spoiling his chances of a big promotion. However, things become complicated when the dead body turns up hanging from a crane in front of the station where Choi works, and he is put in charge of tracking down the killer. As his team closes in on him, Choi begins to disrupt the investigation while trying to determine who trapped him.

“Everyone has moments when they had to do something corrupt, that goes against their principles,” Son said at a press conference on May 6 at CGV Wangsimni. “Who is in the wrong? Were they always wrong? This is what the actors and the director thought about most while making this movie. It’s a hard question.”

The film is fast-paced, with several plot twists along the way that keep the audience second-guessing their assumptions about who is truly evil in the story. However, the core message is always about the human struggle to make the right judgments and the difficulty of painting any action black or white.

“The objective was to toss a character into a complicated situation, and to see how he responds,” said director Baek. “Although it’s a thriller, we put the focus on the emotions of the characters.”

That human focus is carried by terrific performances from the cast, not only from Son Hyun-joo but also from supporting actors Ma Dong-seok, Park Seo-joon and Daniel Choi, who faithfully play their roles in piecing together the plot. Son is able to convey Detective Choi’s inner turmoil through his piercing gaze alone, while Ma offers comic relief with his characteristic charm.

While Son and Ma are known for their previous performances in similar crime action and thriller work, “The Chronicles of Evil” was an impressive transformation for Choi and Park. Choi is known for playing comic roles, but here he becomes a brooding figure who seems to hold the key to the investigation. Park, known for his roles in teen romance dramas, is convincing as a loyal rookie detective who also seems to be holding something back.

The strong portrayals add depth to all the characters involved, making it impossible to say for certain who is to blame for all the chaos onscreen, and ultimately who the victim truly is. In the end, the film is able to chronicle evil actions, without producing a single villain.

“The Chronicles of Evil” opens in local theaters Thursday.

By Won Ho-jung (hjwon@heraldcorp.com)