Sam Phillips (Philip Sayer) and his son Tony (Simon Nash) are playing outside their farm when suddenly the father is abducted by an intense light that falls upon her and kidnapped by an extraterrestrial spacecraft. Three years later, the father suddenly appears, he will return to Earth, but things are no longer equal in their home. His wife Rachel now lives with another man, Joe. This does not trust Sam and Rachel will look at a difficult crossroads, forced to decide between two hombres.Tony soon suspect that his father is no longer the same man who suddenly disappeared and has long ceased to be human. Thus, it will be forced to act to stop the intruder who carries within her body Sam and intends to infest millions of people around the world with their larvae.