School's Out (2018)

A high school teacher throws himself from the classroom window before the terrified eyes of his students. Despite the tragedy, six of them remain oddly cool and unemotional. Pierre, the new substitute teacher, notices the hostile behaviour of this close-knit clique. Smart and precocious, the six teenagers seem to be preparing a mysterious plan after school. Pierre becomes obsessed with them and is quickly sucked into their sinister game.