On an asteroid prison, a group of dangerous aliens known as Crites are set to be transported to another station. The Crites engineer an escape and hijack a ship, prompting the warden to hire two shape-changing bounty hunters to pursue them to Earth. Studying life on Earth via various satellite television transmissions, the first bounty hunter assumes the form of rock star Johnny Steele, while the second remains undecided, thus retaining his blank, featureless head.