Let’s not think too much about the resolution to Stacey Gregg’s haunting “Here Before.” It’s too pat to feel satisfying after all that we’ve invested in that’s come before it.

But what we’ve seen and settled into up to that climax is another sublime performance from Andrea Riseborough, one of the subtlest and most expressive actresses working today. Playing a mother who carries on with her life, her marriage and with raising her teen son after the death of her younger daughter, Riseborough (“The Grudge,””Battle of the Sexes”) gives us documentary-real grief, the kind that you’re supposed to shoulder and soldier through without anybody else seeing it. She makes us understand that grief is a form of haunting.

Laura is in a place where she won’t even let herself be triggered. Finding a tattered pinwheel in her wintry, over-grown Northern Irish garden might give her a moment’s pause, a reverie. But she’s so compartmentalized her thoughts of Josie that she limits her flashbacks to silent memories of adjusting the child’s hairband.

Son Tadgh (Lewis McAskie) may be ruder than usual, and sleepwalking on occasion. But husband Brendan (Jonjo O’Neill) is more about keeping a wary eye out for how his wife is taking it than examining his own feelings.

Only Laura is rattled, in only the most subtle ways, when new neighbors move into the other half of their bedroom community duplex.

“Wee girl puts me in mind of Josie, that’s all.” Megan (Niamh Dornan) resembles the dead girl, and a couple of times, when they’re alone and then when she’s over to dinner, she startles Laura with things she seems to recognize in this strange new town. Serving her a fishsticks sandwich leaves Megan puzzled.

“Are you gonna do the ketchup face?” Josie liked her ketchup drawn in as a smiley face on her sandwiches.

The conflict that’s set up here is between Laura and her family, with Tadgh particularly furious at what he thinks is going on, Laura and Megan’s mom (Eileen O’Higgins) and Laura and her own fragile psyche.

Is she imaging this connection, this ghostly reincarnation that’s moved in next door? And if she isn’t, is she prepared to accept some supernatural explanation?

Riseborough underplays every moment Laura lives through in this spare, moody, perpetually-overcast drama. She not just a mom, living in the reality of keeping their lives going. She’s a woman struggling to do the most basic things to put unbearable grief behind her, wearing a brave face for husband and son.

The grief, “It gets in there and won’t go away,” she explains as more than one person in this compact tale starts to wonder if she’s losing it. Only her mother-in-law seems wholly sympathetic.

“If she’s with you, that’s your business.”

Veteran British TV writer Stacey Gregg, making her feature writing/directing debut, maintains a glum tone throughout “Here Before,” occasionally flirting with spooky, sometimes leaning towards sinister.

Yes, she finds a way to resolve this mystery that makes sense — barely. But she wisely makes this ghost story without ghosts, horror tale without frights, something subtler, more real and disturbing in its own way.

And it helps that “subtler” and “real” are the specialties of her leading lady, who makes Laura as convincingly broken as she is tonally and most assuredly Irish, right to the bone.

Rating: R, for language (and violence)

Cast: Andrea Riseborough, Jonjo O’Neill, Niamh Dornan, Lewis McAskie and Eileen O’Higgins

Credits: Scripted and directed by Stacey Gregg. A Saban release.

Running time: 1:22