A space shuttle crew return to Earth, bringing alien "seeds" with them. These begin to grow into alien life-forms, needing hosts to complete their evolution... When their number reach the Threshold amount, they will be an unstoppable swarm, so it's up to two scientists to stop them beofre it's too late.
Threshold
An astronaut wounded by a meteorite accidentally brings a brood of insects back to Earth. NASA investigator Dr. Home and entomologist Dr. Bailey have 24 hours to find a better way to get rid of them than nuclear bombardment.
