I highly recommend this action/thriller movie.
The story isn't overly complicated but it's engaging and entertaining.
It follows a young North Korean man who is forced to become a secret agent and carry out the mission his father started in order to secure a better life for himself and his sister. He goes undercover as a high school student in South Korea with a list of people he needs to eliminate. As he navigates his new life, he finds himself torn between protecting a bullied girl in his class and fulfilling his mission.

Enjoy the movie without spoilers.