Jerking a character suddenly out of the frame has been a horror movie staple for years now. There’s nothing more chilling than an abrupt vanishing carried out right before our us, a victim, wild-eyed with terror, ripped away into the dark unknown.

But the way Rose Williams is yanked, lifted, tugged and twisted in “The Power” takes it to a new level. Writer-director Corinna Faith (“Ashes”) contorts her leading lady in ways that startle and chill in a movie that’s more about tone than scary jolts.

It’s an immaculately realized period piece set in the lowering gloom of an old, poor but tidy East London hospital in 1974, when Britain’s Conservative government carried out selective blackouts as a measure to combat coal miners who’d gone on strike.

“You couldn’t have picked a worse day” Val (Williams, of TV’s “Medici”) is told by “Old Starchy,” the matron (Diveen Henry) in charge of nurses who gives newly-graduated Val the once over before starting her new job.

The hospital’s patients are mostly being transferred out, with just a couple of wards kept open for the night, lit by candles or kerosene lanterns for the planned blackout.

Val is eager, compassionate, and not wholly at odds with the older staff. But she has some sort of history, something sneering ex-classmate Babs (Emma Rigby) remembers and has passed around. Irish Terry (Nuala McGowan) doesn’t sweat that. Much. She’s got bigger worries.

“A place people die in should never be allowed to get that dark.”

Val finds herself encouraged by Dr. Franklin (Charlie Carrick), who sees her way with children, and punished by the matron.

“You need an iron will” for pediatric nursing, she hisses. “Not a ‘feel for it.'”

Maybe working the lonely, scary and dark night shift will make that clear.

But once the lights go out, spooky things start happening around Val, and to her. What’s going on? And is this like what happened “before?”

There are pacing problems that keep this picture from reaching its full potential, and truth be told, there’s a bit of stiff-upper-lip under-reacting to the supernatural stuff that befalls Rose and her colleagues.

But as candles blow out on their own, Rose is pulled hither and yon and a fearful child (Shakira Rahman) with little English at her command tries to articulate her terrors, “The Power” works on you.

Not as well as it works on Nurse Terry, perhaps, who is not having this, perhaps because of the novel she’s reading in between rounds. It’s “Carrie,” the 1974 hit by that new American fright-writer.

Williams, playing a young woman fighting her fears even as the hint of recognition of what she’s dealing with keeps her from flipping out entirely, makes us believe Val’s peril and believe in her ability to fight it.

Which “The Power” more than just a “nice try,” even if it’s not quite all the terror you’d hope Faith might wring — or yank — out of it.

MPA Rating: unrated, violence

Cast: Rose Williams, Emma Rigby, Diveen Henry, Charlie Carrick and Shakira Rahman

Credits: Scripted and directed by Corinna Faith. A Shudder release.

Running time: 1:32