Five high school misfits are called for detention on a Saturday night by their teacher but as the night closes in an elite group of Space Ninjas begin their invasion on the secluded school. After the Space Ninjas kill the teacher, the students are left to fend for themselves, as they try to escape the school grounds and survive the night.

The world is overrun by mind-controlling aliens called the Sky Beasts. Six people hide out in an abandoned building. But when one of them is exposed to the aliens, paranoia among them proves to be just as deadly as any threat from the sky.