Four friends who attend high school together as second-year students are kidnapped. Steel collars are placed around their necks, with chains attached to a torture chair in each corner of the room. A large cage dangles from the ceiling, in which a silent young boy dressed in all white is trapped. As the girls try to escape, a voice tells them that they are being put through a test with only two possible outcomes: either everyone will die, or one girl will die and the other three will survive.