They’re both ancient history, at least in the pop culture sense, but it’s helpful to remember that Daphne du Maurier was Alfred Hitchcock’s favorite novelist when you’re watching “My Cousin Rachel.”

Hitchcock filmed her romantic mysteries “The Birds, ” “Jamaica Inn” and most famously “Rebecca,” and the thing that made the filmmaker and the writer so hand-in-glove was their shared love for surprise twists.

So no matter how often Rachel (Oscar winner Rachel Weisz) turns on the tears, how sinister her every offered “Cup of tea?” seems, no matter how paranoid the letters from her late husband, read by his enraged cousin (Sam Claflin), alleging a marriage to a spendthrift that has become a deadly trap, keep your smug “Oh she DID it,” to yourself.

Because you never know. Or do you?

That’s the mystery facing young Philip Ashley (Claflin, of “Me Before You”) as he tries to piece together what happened to his late cousin and guardian, the man who left him a vast Cornish estate in late 18th century Cornwall. Cousin Ambrose took sick, went to Italy for the cure, met a charming widow, married her, got ill again and died.

Much of this played out in letters to his young ward, Philip. And as those letters turn paranoid and accusatory, Philip dashes to Italy to save Ambrose, only to arrive too late.

The new college graduate is enraged, threatening the widow’s poncy Italian lawyer when the man insists Ambrose died of a brain tumor.

“I believe NOTHING of what you told me.”

To his godfather (Iain Glen) back in Cornwall, Philip threatens his revenge, “in full measure,” upon this femme fatale. If ever they meet.

But they do. She comes to visit. It turns out, she never changed Ambrose’s will. She inherits nothing. She is sad, lightly flirtatious,  delicate, cries easily. Philip and seemingly every other man within her reach is instantly smitten.

And he impulsively starts trying to set her up for life, ease her pain and give her a rightful inheritance. His advisers’ raised eyebrows and her testy protests of the “shame” his attentions bring her are to no avail. He’s let her wrap him “around her little finger,” but only we in the audience and his godfather’s daughter (Holliday Grainger) see that.

But not Philip. And with her every proffered cup of “herb tea,” every fever and fevered hallucination that follows, we fear for this young fool’s fate.

Adapter-director Roger Michell (“Notting Hill,” “Venus”) gives this quite old-fashioned mystery the jolt of arresting camera work — extreme closeups, handheld horseback jaunts, painterly framing. The production design is of a grubby, under-maintained world of land-rich aristocracy where cleaning, painting and buying new clothes don’t figure, all set under perpetually grey English skies.

The servants are crusty, adoring and treated as egalitarian equals — at least to a greater extent than is normal for such class conscious period pieces.

Michell looks to deepen the mystery, with hallucinatory flashbacks making us wonder if Philip’s constant accusatory/infatuated flips aren’t as much his problem as Rachel’s. Claflin gets across the “rashness” of du Maurier’s hero, and Weisz, experiencing a career renaissance thanks to “Denial,” “The Lobster” and this, gives vulnerable, and frankly shady shadings to Rachel.

We have many facts to work with, some of them contradictory. Which of them point to an actual resolution?

Best of all, Michell ensures that the cryptic finale to “My Cousin Rachel” isn’t so much a solution as an invitation to an argument on the drive home from the cinema.

MPAA Rating: Rated PG-13 for some sexuality and brief strong language.

Cast: Rachel Weisz, Sam Claflin, Iain Glen, Holliday Grainger

Credits: Written and directed by Roger Michell, based on the Daphne du Maurier novel. A Fox Searchlight release.

Running time: 1:46