The Substitute(2015)

School can be torture.

The Substitute is a psychological thriller about a young teacher who accepts a position at an exclusive private school. She quickly realizes the boys wield an unsettling power over the girls, whose fear intensifies as the students' behavior grows more menacing. When she investigates the source of their terror, she discovers an ominous locked door hidden at the back of the classroom—a discovery that forces her to confront something far darker than typical school dynamics. As tensions escalate, the teacher must uncover what lies behind that door and the sinister secret binding the students together before it's too late.