As a teenager possessed by an alien, Saoirse Ronan makes a strong impression in this decent sci-fi tale, based on Stephenie Meyer’s book.

Ronan’s feisty heroine fancies one guy, while the alien is drawn to the other.

Borrowing from Invaders of the Body Snatchers, Meyer wrings some chills from the notion of a parasitic alien race taking over human bodies and erasing their minds and memories.

Max Irons and Jake Abel make rather bland romantic leads, but Ronan does an excellent job of conveying her dual characters’ frisky internal dialogue, while Diane Kruger’s alien and William Hurt’s rebel leader also make strong impressions.