A family with a daughter deep into Wednesday Addams cosplaying shows up in a small midwestern city, and people start dying. Suicides, deaths that don’t look like suicides, heart attacks, always with the little girl giving somebody the evil eye, always after meeting the insurance salesman husband in the family.

And there’s this serpent relic, a tiny stick with a metal snake wrapped around it, that turns up on the scenes of some of the deaths.

Somebody or some thing — THAT thing — is “The Harbinger” of bad things to come, “evil things.”

Here’s a promising horror tale of a Deal with the Devil, a Native curse, an “evil” child and a Native woman (Irene Bedard) to explain it all — “I practice the arts!” — to the hapless and maybe implicated parents (Will Klipstine, Amanda McDonald) of a child (Madeleine McGraw) who gives everybody she meets the willies.

There’s also his cadaverous, wild-eyed stranger in a trench coat who seems to be pulling the strings. When your only billing is “Creepy Man”(Bruce Bohne), any conclusions we leap to about you are going to be on the money.

But “The Harbinger” is a dawdling, chatty, over-explained thriller that fritters away the promise of a story that packs a lot of proven horror tropes into a single package, an 85 minute film in a 114 minute box.

A few decent effects — gruesome murders, characters dangling from an unseen noose or the invisible hands of the Devil — are undone by the masked demon we see, a plot that trips over itself more often than not and the dithering pacing.

The daughter’s central role feels like a red herring, even though one and all figure she’s the creepiest one of all. We see her diagnosed with schizophrenia in an opening scene, see the family skipping from town to town thanks to Dad’s “work.” But the evil child trope is abandoned, or simply misplaced.

When the Native spirit woman Floating Hawk (Bedard of TV’s “The Stand”) intones, “Only death can set her free,” we’re a bit skeptical. As is her father, understandably, and in more ways than one.

As a police detective (Vince Duvall) dives into linking the deaths, and gets ahead of himself trying to railroad this “insurance” man into jail, as the locals shun the newcomers who seem to visit death upon everyone they meet, we wish they were seeing what we and the Snyder family was seeing.

“Kill yourself” scrawled, backwards in blood on a wall, for starters.

All the explaining and the third act’s chase/quest elements aren’t enough to save the day.

Take the title as a warning. This isn’t a “Harbinger” of disaster. It’s just all portents of evil, and precious little that’s entertaining comes with it.

Rating: PG-13, violence

Cast: Will Klipstine, Madeleine McGraw, Amanda McDonald, Bruce Bohne, Vince Duvall and Irene Bedard.

Credits: Directed by Will Klipstein, scripted by Amy Mills and Will Klipstein. A Screen Media release.

Running time: 1:54