The author of the “Twilight” regime, Stephenie Meyer, is not resting on her vampire laurels. Her 2008 novel, “The Host,” has arrived in movie theaters, and there is not a bloodsucker in sight.

That technical difference noted, one might observe a few similarities between the Young Adult-oriented properties. “The Host” also puts a teenage heroine through a supernatural dilemma, pulls her between two equally hunky suitors, and fills her life with amorous attention that flushes the cheeks but steers mostly clear of the overtly sexual.

This heroine is Melanie (played by Saoirse Ronan), one of the last remaining humans in a world that’s been taken over by invading aliens called Souls. In the opening sequence, she is transformed into a Soul, but the Melanie part of her personality remains stubbornly present; we hear Melanie’s voiceover as the silver-eyed Soul named Wanderer tries to go about her business.

Some of you may be picturing Steve Martin in “All of Me,” stuck with the spirit of Lily Tomlin in his head. And, oddly, some of “The Host” plays as comedy, as Melanie’s quasi-Valley Girl patter pops out at the strangest moments (the “Twilight” saga had a tendency for this mood-breaking humor, too).

Our divided heroine falls in with a renegade band of humans, led by Melanie’s Uncle Jeb (William Hurt, big-bearded). They don’t know whether to kill Wanderer — now called Wanda — and the audience doesn’t know why Melanie doesn’t try to signal to them that she’s still inside.

The triangle comes in the form of Melanie’s boyfriend Jared (Max Irons, son of Jeremy), who still loves Melanie but hates Wanda. Ian (Jake Abel), on the other hand, is beginning to really dig Wanda, even if she’s obviously a Soul.

Confusing? Don’t worry. Director Andrew Niccol is going to take a lot of time to explain all this. A lot of time. Most of which is spent inside the caves that hide the survivors, which are beautifully photographed but a little monotonous after awhile.

“Atonement” and “Hanna” star Saoirse Ronan is definitely the actress you want to carry a movie like this, although her silvery contact lenses rob her of her most expressive feature. The boys don’t have much of a chance to shine with her around.

Despite the lack of action (there are no werewolf battles here), “The Host” isn’t terrible, but in some basic way it lacks color. The “Twilight” movies may have been chided for their cheesiness by us unbelievers, but in those installments where they didn’t grind to a complete halt, they did serve up some lurid, crazy fun.

“The Host” doesn’t really have anything like that. It’s a sober affair, brought to life by a lead actress who can justify the clarity and commitment she brings to a climactic emotional speech. Ronan is good, but boy, the movie around her is dull.

“The Host” 2 stars

Another idea hatched from “Twilight” author Stephenie Meyer, this time about a teenage girl whose body is taken over by a silver-eyed alien Soul during Earth’s capitulation; her divided self toys with two different hunks during her stay with surviving humans. The movie’s dull overall, even if Saoirse Ronan’s commitment to the lead role is impressive.

Rating: PG-13 for violence, subject matter

Showing: Alderwood, Cinebarre, Everett Stadium, Galaxy Monroe, Marysville, Stanwood, Meridian, Sundance, Thorton Place, Woodinville, Cascade Mall.