Harry Bromley Davenport's Xtro opens when a young boy, Tony (Simon
Nash) sees his father, Sam (Philip Sayer) abducted by an alien spacecraft.
Three years later Tony, his mother Rachel (Bernice Stegers), and her
lover Joe (Danny Brainin) are living in London with their French au
pair Analise (Maryam D'Abo). Unbeknown to them, Sam has returned to
Earth in extraterrestrial form. When the Xtro-Sam rapes a young woman
(Susie Silvery), her body swells grotesquely until Sam is reborn full-grown
and apparently human.
Following his rebirth, the film charts Sam's troubled return to the
family and his recruitment of Tony, Tony's transformation of Analise
into an alien egg-producing cocoon, and the permanent reunion of father
and son. In the penultimate moments, Rachel watches Sam, now in alien
form, take Tony's half-human, half-Xtro hand, and lead him aboard
a spaceship. She then returns home to discover Analise's eggs.