In an attempt to colonise Mars, 21st-century scientists seed the planet with algae to absorb sunlight and purify the atmosphere, and cockroaches who in turn spread the algae as they feed. 500 years later, the first manned mission to Mars loses contact with Earth, and a second ship is sent to investigate.
A small rural town finds itself in the grip of an infection which send its hosts into a violent, homicidal frenzy.
