Bella Thorne and Dermot Mulroney star in this supernatural thriller in which the world is inhabited by ghostly “Remnants” of people who were killed in a cataclysmic event.

This supernatural thriller starring Bella Thorne and Dermot Mulroney should provide glossaries to the audience. Depicting a society in which ghosts walk among the living after an apocalyptic disaster, the film freely indulges in the use of terms like “The Event,” “Energy Wave,” “Spectrum Transference” and “Remnants” (“Rems” for short, try to keep up). I Still See You is painful to watch, and having to learn all the new jargon only makes it feel like an academic chore.

Thorne plays Veronica, a high school student living in a small Illinois town not far from Chicago, where The Event occurred 10 years earlier (doesn’t that city have enough trouble?). The Event created an Energy Wave that killed much of the world’s population. The victims aren’t exactly gone, however. Their spectral Remnants linger on silently, as if they don’t really know they’re dead. The result is a world in which we’re all like the little kid in The Sixth Sense.

Veronica has become used to the hovering, ghostly presence of her father every morning at the breakfast table, reading the newspaper looking like he doesn’t have a care in the world. She’s more discomfited by the frequent appearances of a young, hunky Remnant (Thomas Elms) who shows up in her bathroom looking like an underwear model. Literally, because he’s wearing tight underwear. This happens a lot because Veronica, like so many attractive young women in movies of this type, takes an inordinate number of showers. Like the other Remnants, this one doesn’t have anything to say. But he does seem to be imparting a warning when he writes the word “Run” on the bathroom mirror.

Veronica reports the phenomenon to her science teacher Mr. Bittner (Dermot Mulroney, probably missing the days when he co-starred with the likes of Julia Roberts), who lectures constantly about Remnants in his class. (He likens The Event that produced them to such real-life tragedies as Hiroshima and Nagasaki, references that shouldn’t be allowed in movies this bad.) Veronica also confides in Kirk (Richard Harmon), the recently arrived transfer student who’s obsessed with Rems and who broods so much he comes across like a potential school shooter.

The ensuing plot machinations involving a murdered young girl, a crazy scientist (is there any other kind?) and a government conspiracy are too convoluted and tiresome to fully relate. Suffice it to say that when one of the major characters is revealed to be a villain, the only thing surprising is that it was apparently intended to be a surprise.

Director Scott Speer (Step Up Revolution, Midnight Sun) manages to sustain an atmosphere of spooky tension, abetted by Simon Dennis’ gloomy cinematography and Bear McCreary’s ominous musical score; indeed, several of the Remnant appearances prove effectively creepy. But the film, based on the 2012 YA novel Break My Heart 1,000 Times, feels interminable in its sluggish pacing, contrived plotting and endless wonky exposition. Viewers are less likely to feel scared than that they should be taking notes.

Production company: Gold Circle Films
Distributor: Lionsgate
Cast: Bella Thorne, Dermot Mulroney, Richard Harman, Louis Hertham, Sara Thompson, Shaun Benson
Director: Scott Speer
Screenwriter: Jason Fuchs
Producers: Paul Brooks, Leon Clarance
Executive producers: Jason Fuchs, Douglas Jones, Bad Kessell, Jeff Levine, Scott Niemeyer, Laure Vaysse
Director of photography: Simon Dennis
Production designer: Kevin Bird
Editor: Paul Covington
Composer: Bear McCreary
Costume designer: Heather Neale
Casting: Eyde Belasco

Rated PG-13, 98 minutes