“Pompeii” is like a low-rent “Titanic,” with a rich girl and a poor boy falling in love in the shadow of Mt. Vesuvius days before its famous eruption in A.D. 79. You need something to fill the time before the volcano blows its top, though, so to pad out the story, “Pompeii” is also an uninspired “Gladiator” retread. It’s two Oscar-winning movies crammed into one 105-minute waste of time and money!

Directed by technically proficient but artistically remedial Paul W.S. Anderson (“Resident Evil”), this silly melodrama stars Kit Harington — Jon Snow on “Game of Thrones” — as a Celtic slave named Milo who was captured as a boy by the Romans after they slaughtered his village. Milo is an unusually strong and lethal fellow when it comes to hand-to-hand combat, so the Romans have added “gladiator” to his list of duties. (Adewale Akinnuoye-Agbaje plays his gladiator pal, Atticus, one of maybe two interesting characters in the movie.)

Milo and Pompeii’s fairest daughter, Cassia (Emily Browning), have their “meet-cute” when one of her horses breaks its leg and he tenderly euthanizes the poor beast by snapping its neck with his bare hands. Cassia sees in Milo the sort of sensitivity that is rare in slaves, not to mention the ability to kill large beasts that is rare in everyone. But it would be folly for a high-born girl to have dalliances with a slave, of course, and Cassia’s parents (Jared Harris and Carrie-Anne Moss) are willing, if hesitant, to marry her off to a conniving Roman senator, Corvus (Kiefer Sutherland, made entirely of ham), in exchange for his promise to invest in Pompeii’s infrastructure. Meanwhile, there are occasional earthquakes and sinkholes, to remind us that trouble is imminent.

The paper-thin characters, wan dialogue, and rehashed plot make the volcanic debris a welcome sight when it finally arrives, 70 minutes in. Yet even those eager for disaster porn will surely come away disappointed, both by the quality of the CGI devastation (it’s low…) and the quantity (…and such small portions). Even the one thing Anderson is usually good at, composing striking visuals, is in short supply here. It’s such a shame to be disappointed by a movie, more so when you weren’t expecting much in the first place.

D+ (1 hr., 38 min.; PG-13, abundant slashing, stabbing, and beheading, plus disaster violence, all of it depicted without much blood.)