Pluto (2012) on Netflix

Plot summary

At a prestigious South Korean high school, seniors compete for places at the country's best universities, and a group of the school's top students holds privileges that keep their rankings high. Kim Joon arrives as a transfer student and is shaken by his first examination results. He learns that the group shares notebooks holding examination information and asks to be included, and the members set him tasks he must carry out before they will let him in. When the top student, Yoo-jin Taylor, is found dead near the school, evidence and student testimony point to Joon, and the police arrest him. He is released, returns to the school, and holds the group in a hidden basement, where he demands to know what they have been hiding.