The lady of the house has been through trauma or some sort. It’s wrecking her sleep and gutting her short term memory. All the medication in the world is no help.

Then Diana shows up. Christine doesn’t remember hiring a Filipina cook, maid and and care-giver. But Diana is all smiles, all-in and ready to be of service.

“I can help you, Christine.”

And sure enough, she can. With a few herbs burned as incense, an incantation over hair and nail trimmings, and even a dash of tickling, Diana can feel her humanity coming back, a children’s clothing designer whose zest for work returns with the childhood mantra she repeats before any big meeting.

“Lovely shoes, lovely shoes, make me win and never lose!”

Sure, Diana’s offering a “different kind of medicine.” But it works. No harm in that, right?

“Nocebo” is a tidy and tight-as-a-tick thriller about a woman who wonders what is real and what isn’t in a life that’s coming off the rails, until her live-in help arrives.

It’s a horror movie with a hint of mystery, a chill or two and a dash of pathos. And as the ever-helpful, pushy Diana, Chai Fonacier (“Jesus is Dead”) brings a metallic menace to a role we and the people she comes to work for are meant to treat warily.

What’s her game, and why is she helping this rich woman (Eva Green) and her bratty daughter (Billie Gadsdon), over the objections of the suspicious husband of the house (Mark Strong)?

The Garret Shanley script is just cryptic enough to make us ponder its mystery, but not so clever that we don’t figure out where this is going before the movie’s midpoint.

Sturdy direction, generously chilly sound effects and downbeat and downright sad flashbacks engage us and tell us how Diana gained her “gift,” how it’s been a curse and why she has come to this Irish townhome and this brittle family.

“Nocebo” — a medical term describing the psychological trickery that the mind plays when it expects the worst — never quite sings, never goes as Gothic and over-the-top as one might like and only tugs at the heart when it should tear at it.

The performances, script and tone seem to settle for “menacing” when more terrified reactions are in order. It’s as if everybody here has left things to fate and accepts the horrors to come and refuses to be shocked, just resigned to it.

One and all settle for “watchable” when they could and should have summoned up much more.

Rating: unrated, violence, profanity

Cast: Eva Green, Chai Fonacier, Billie Gadsdon and Mark Strong

Credits: Directed by Lorcan Finnegan, scripted by Garret Shanley. An RLJE/Shudder release.

Running time: 1:37