Before the school year starts, students and teachers take grade preparation classes to prepare for the upcoming school year. However, when a severe storm knocks the power out in the school, the front doors mysteriously are locked from the outside, and students begin coming up missing one by one, the remaining survivors band together to try to escape. They soon discover that a form of early homo-sapiens has been watching and preying on them one by one. Now it's up to the remaining teachers and students to make it out alive before they become victims as well.