This week’s post-apocalyptic movie about the battle between humans and vampires is called “Priest.” It stars Paul Bettany as a priest who defies his religious superiors to prevent the slaughter of innocents. It is directed by Scott Stewart, whose last film, “Legion,” was completely different. It starred Paul Bettany as an angel who defies God to prevent the slaughter of innocents. Stewart and Bettany are the Scorsese and DeNiro of mediocre, CGI-laden supernatural thrillers.

Bettany plays a priest named Priest. I guess he was so priest-y there was nothing else he could be called. In this world, priests were once recruited based on their natural ability to fight vampires, which was evidently the church’s main concern. But now the war between man and vampire is over (we won!), and the remaining handful of vamps live on isolated reservations or in secret hives, so priests are no longer needed. In fact, even if a priest becomes aware of dangerous vampire activity, he is not allowed to use his priestly powers to get involved.

That is what happens to Priest. He lives in a big, Orwellian city full of high-tech gadgetry and surveillance equipment, while his brother, sister-in-law, and niece live out on the frontier. Priest gets word from the town sheriff, Hicks (Cam Gigandet), that his kinfolk were ambushed, and his niece, Lucy (Lily Collins), abducted by a herd of vampires and their human slaves, known as familiars. Priest wants to rescue her, but his boss, Monsignor Orelas (Christopher Plummer), says it is forbidden and should be left to the local civil authorities.

“To go against the church is to go against God!” the Monsignor declares, eight or nine hundred times. Well, guess what. PRIEST IS GONNA GO AGAINST GOD, THEN! AW HELLS YEAH!!

Priest and his fellow priests have some enhanced physical powers, including the ability to leap to great heights and to be good at throwing ninja stars. Hicks, a regular dude, has good aim with a six-shooter. Since he’s in love with Lucy, he’s determined to bring her back alive even if she’s been infected by the vampires. He and Priest stop every few minutes to have an argument over whether Priest will allow that, or whether Priest will have to put her down.

There’s a lot of stopping and arguing in this movie, plus a lot of stopping and having somber spiritual chats, and a lot of stopping and not doing anything. Basically, for a movie about a rogue priest and his sheriff friend fighting the forces of evil, “Priest” is exceptionally light on actual fighting. When it happens, it’s cool: slow-motion, “Matrix”-y stuff, creepy-looking vampires (they’re monsters, not humanoids), engaging action. But it’s in short supply, and the dialogue in between is generic, the film’s mythology poorly explained.

The film is based on Min-Woo Hyung’s graphic novels — based very, very loosely on them, from what I gather. Stewart’s emphasis is style rather than substance (a common problem in this genre), and he certainly creates some striking images, particularly in the sequences set in the stark wastelands. (The cinematographer, Don Burgess, gave a similar look to “The Book of Eli.”) Much about the story seems like it might have been interesting if it had been more fully explored: the parallels to the Western genre, the way society turned against the priests, the people’s false sense of security in their big cities. Instead, the story feels rushed, as if artificially squeezed into an 87-minute time limit. It’s too good-looking to be dismissed entirely, not bad enough to be worthy of outright scorn, but not good enough to watch, either.

C (1 hr., 27 min.; PG-13, one F-word, a fair amount of blood and violence -- kind of borderline for a PG-13.)