In the near future, a race of nomadic parasitic aliens -- called "Souls" -- have taken over humanity. The jellyfish-looking aliens are injected into humans, whose minds are then suppressed as the aliens take control, turning their hosts' eyes silver. Melanie Stryker (Saoirse Ronan), a member of the dwindling human resistance, purposely diverts a group of aliens by throwing herself out a window. But she survives and is implanted with her new alien Soul, Wanderer. Unlike other human hosts who fade away completely, Melanie's consciousness continues to speak to Wanderer and persuades her to evade her alien interrogator (Diane Kruger) and go to the desert hideout where Melanie's boyfriend, Jared (Max Irons), and little brother, Jamie (Chandler Canterbury), are staying. Only they don't see Melanie -- just the alien who's taken her body. Slowly, Wanderer -- dubbed Wanda by Melanie's wise uncle Jeb (William Hurt) -- starts to make alliances, including a confusing attraction to Ian (Jake Abel), Jared's more open-minded friend.
As sci-fi movies go, THE HOST is one part Invasion of the Body Snatchers and three parts maudlin romance. Director Andrew Niccol doesn't bother with much world building except for the fact that the pacifist Souls all have a thing for wearing shades of white and driving souped-up silver Lotuses; there's no real explanation for the hypocrisy of a supposedly pacifist alien race thinking that it's all right to parasitically control an entire species. And while reading the back and forth between Wanderer and Melanie made perfect sense in the book, the movie translates that by having a narrated dialogue with two different inflections -- Wanderer's smooth tones and Melanie's faux Louisianan accent.
While teen (and adult) viewers who are only interested in the steamy kisses and the mind-bending love quadrangle will be content, most audiences will laugh at The Host's unintentionally funny moments -- like pretty much every time the Melanie voice speaks. Ronan, who's riveting in films like Atonement and Hanna, is deserving of better, although at the very least she manages to pull off her romantic moments with both Melanie's love Jared and Wanda's suitor Ian with conviction. The movie is more of a frothy alien romance than a true science-fiction thriller