Putting John Simm ("Life on Mars," "Doctor Who") together with Mira Sorvino ( "Falling Skies" lately, "Mighty Aphrodite" back when) is a promising start for a series. He's like something out of Depression-era Warner Bros., a bantamweight tough guy with a sensitive streak; she's an always-interesting actress, good with drama, good with comedy. That Glen Morgan, a veteran of "The X-Files" developed it, and that Julie Gardner (who shepherded the rebirth of "Doctor Who") is an executive producer, also feels auspicious.
And yet. Though some of it is effective, much of it is not, for all that it strong-arms the viewer with dark atmosphere and upsetting events. (Watch out for that cat.) It is, in its opening hours at least, a moody muddle.
Nearly every frame reminds us with that we are in the realm of the uncanny, the ominous, the dangerous. There are no baseline moments of normalcy to depart from or return to.
From the get-go director Eduardo Sanchez ("The Blair Witch Project") lays on the slow motion, the extreme close-ups, the shifting focus; genre go-to composer Bear McCreary ("Battlestar Galactica," "The Walking Dead," "Outlander") provides chilly underscoring. Simm and Sorvino — he's a cop-turned-writer, she's a fancy lawyer, they're married — are allowed the merest fraction of a normal conversation before things get completely abnormal between them.
The action in the opening episodes takes place mostly in Washington and Oregon, which is another way of saying "Made in Canada"; it's a show that can give you seasonal affective disorder right in your Southern California living room. And it labors under the weight of some tired tropes — secret societies guarding secret knowledge through the ages, people willing to do anything to live forever.
It feels like such old business. But the familiar is as much a part of genre drama as the strange, and it is possible that for some viewers, everything I've said here will only serve to whet their whistle.
Robert Forster (merely a guest star, sadly) does inject a feeling of ordinary business into an early scene, even as he does extraordinary things, a flag that partner James Frain ("The Tudors," "Grimm") later does his best to carry, with some success. His character — I can't really say what he's up to, not because it would ruin things for you, but because his mission, apart from that involves shooting people, is obscure — is the most interesting of the adult characters here. I am pretty sure he is a villain.
Also impressive, and more genuinely creepy than anything else in "Intruders," is 10-year-old Millie Brown, playing a 9-year-old inhabited by some much older, not very friendly spirit. That she pulls it off — that there is something oddly mature about her face helps — is its own kind of weirdness. I will keep my fingers crossed that the rest of the show catches up with her.
Where: BBC America
When: 10 p.m. Saturday
Rating: TV-MA (may be unsuitable for children under the age of 17)