'Test Day' follows a group of teachers who are chosen to write questions for the College Scholastic Ability Test, the high-stakes exam that dominates South Korean life each year. According to Yonhap News, the chosen writers are kept isolated from the outside world for 40 days, and the comedy is built on the clashes that follow.

The film is the directorial debut of Lee Yong-jae, who previously wrote the screenplays for 'The Mathematician in Wonderland' and 'Harmless'.

Who are the main characters?

Lee Sun-bin plays Maeng Bo-ram, a young teacher who joins the panel after a computer error. Her character is driven by a desire to help students and challenges older panelists who hold authority over the process. Yoo Jae-myung plays Moon Ju-yeol, the panel chairman, a graduate of a top university's Korean language department who is intelligent but self-interested.

What did the actors say about their roles?

Lee Sun-bin said she had never seen a story about question writers before and found the script refreshing. She also said she felt the character was rare in her career, and she dropped her usual look to show Maeng Bo-ram's innocence.

Yoo Jae-myung said he did not want the character to seem like a simple villain. In his words, the core of the role is a grown-up who cannot apologize, and he was drawn to the film's black comedy tone.

For international fans

Lee Sun-bin and Yoo Jae-myung are both well known in South Korea for film and television work. The College Scholastic Ability Test is a major event in Korean culture, and the film offers a satirical look at the pressure surrounding it.