A television crew are following an emergency fire department for their show. The department gets a call to an apartment complex.
Reporter Ángela Vidal (Manuela Velasco) and her film crew follow the fire fighters to the apartment where an old woman has been reported to be in distress. When they arrive the woman attacks the fire fighters.
They try to take the injured man outside only to find that the building has been sealed and everyone inside has been quarantined.
Soon a man from the health department comes in to look at the apartment residents. He says that a strain of rabies has infected the residents. Soon more people are infected and attacking everyone.
This Spanish horror film is very scary and intense. It spawned three sequels and an American remake but this is the best one.