'Jinn'

William Atherton in "Jinn." (Exxodus Pictures)

Despite OK visual effects, a few chills and some newfangled movie monsters, writer-director Ajmal Zaheer Ahmad's supernatural thriller "Jinn" often feels like half of an old grindhouse double bill. It's a watchable if rather convoluted effort.

The titular jinn, according to Eastern mythology, are one of three races created "In the beginning…" (the other two are man and angels). Conveniently — for a horror film, anyway — the mysterious jinn are nothing if not flexible. These time- and shape-shifting beings can be good or bad, peaceful or violent, invisible or in your face (at times, they resemble upright fireplaces). Whatever, you want them on your side.

Unfortunately for Shawn (Dominic Rains), a model-handsome Michigan auto designer married to the equally pretty Jasmine (Serinda Swan), he must suddenly do battle with a vicious sect of the jinn, the Shayateen, because of a family curse that stretches back to 1901. Suffice to say that this ancestral history is news to Shawn, and it's delivered the old-fashioned way: on a VHS tape.

PHOTOS: Behind the scenes of movies and TV

What follows is a frantic few days in which Shawn must collaborate with an unlikely trio of jinn experts — a shadowy priest (William Atherton), a protective tough guy (Ray Park) and a manacled mental patient (Faran Tahir) — to learn how to fight the fiery Shayateen at their own miserable game and, y'know, save the world. This demands that, among other things, Shawn pass an ancient ritualistic test called the Chillah (don't ask).

Meanwhile, Jasmine, who may or may not be pregnant with Shawn's child, has allegedly been abducted by the bad jinn. Cue the stacked deck.

Magical swords, evil doppelgangers, a sexy black muscle car, an unremarkable final showdown and lots of first-draft dialogue factor into this thankfully brief (about 80 minutes plus end credits) frightfest.

As for the film's closing promise: "The Jinn will return" — don't hold your breath.

calendar@latimes.com

-----------------------------

'Jinn'

MPAA rating: PG-13 for intense sequences of violence and terror

Running time: 1 hour, 37 minutes

Playing: In general release