This Spanish horror movie steals ideas from at least three different major films including Alien, Predator, and The Andromeda Strain as it tells the story of three American teens on vacation in Spain who drive their RV into a tiny Spanish town where a large piece of Skylab has fallen and infected the town with a parasitic alien microbe that drives human beings insane and turns them into horrible mutants. At the same time, a scientist from NASA arrives to his agency's secret location beneath an ancient Spanish castle to meet with the member of the original team who survived the microbe. He shows the new scientist the ruined body of one of the men. During the examination, some of the dead man's blood gets on the survivor and suddenly he is infected. The scientist wants to use him to create a serum, but the victim panics and kills himself. The scientist finds the tourists, and then to test out his vaccine infects himself with the virus. He promptly orders the American military to fire-bomb the town so that none of the residents will escape and spread the horrible microbe. He then injects the youths with his serum and dies. Just before the military drops the deadly napalm, the youths in their RV manage to crash the blockades in the town. They make it to a gas station and there find themselves assaulted by a terrifying alien being who bursts from the chest of a dead attendant. The creature tries to scale the RV's windshield. Fortunately, the clever driver simply turns on his windshield wipers, knocks it to the ground and then runs it over several times. The survivors begin to celebrate, until they realize that their driver has a nose bleed. This means that he too has been infected and all is lost.
~ Sandra Brennan, All Movie Guide