A morose, motherless teen finds out a few things about himself and his gene pool when his alcoholic, dying granny comes to stay with him in “Juniper,” a curtain call drama built around a fine turn by screen legend Charlotte Rampling.

Actor turned writer-director Matthew J. Saville’s debut feature makes for a dry, unemotional blend of dark comedy and co-dependency, scenic but desultory, even when Rampling is at her best.

New Zealand native George Ferrier stars in this Kiwi coming-of-age story about a boarding school kid who comes home to help his widowed father (Marton Csokas) deal with Dad’s English, globe-trotting mother, who is to move in with them.

Granny Ruth isn’t the warmest creature, a brittle conflict photographer who took to gin (giving the film its title) long ago, and expects to maintain her bottle-a-day habit while her broken leg heals. As she is in her 70s, that’s a bit hopeful on her part, and on medical science’s.

Grandson Sam doesn’t know her and doesn’t want to get to know her. He’s never recovered from the loss of his Mom. And Dad can’t wait to find an excuse to flee the country to “settle” Ruth’s affairs back in the U.K. Ruth never even told him who his father was, so he has his reasons.

With Sam motorbiking out into the woods to prep a noose for himself, is there anything Ruth can or will do that can mend this broken child and breaking family?

Rampling, recently seen in “Dune,” “Benedetta” and “Red Sparrow,” a screen fixture since her modeling youth (“Hard Day’s Night,” “Zardoz”), nominated for an Oscar for “45 Years,” should have been nominated for “The Verdict,” sports a salty, imperious presence here, a tough broad who has seen it all, lived it up and isn’t inclined to take any guff, even in her current and perhaps terminal infirm state.

“Do the girls like you?” is her first question of her grandson.

“Which wars?” did she cover is his to her. “Most of them,” she shrugs.

They never quite connect, engaging in their own war of wills instead. She’s also dryly scrapping with her nurse (Edith Poor), who is both a caregiver and drink mixer, and more oddly, a devout Christian who is also a vice-enabler. She fetches an Anglican priest for Ruth.

“I thought you might like to talk.”

“Why did you think that?”

The film’s one real scene of sharp banter and real conflict comes here, Ruth cynically baiting the priest with a bribe, him losing his temper — “You do deals with the Devil, not with God!”

Saville’s story — supposedly borrowed from his own childhood — has few incidents that one would go so far as to describe as “action.” Everything is interior and emotional and approached at arm’s length. We get a load of Sam’s unhappiness and his short temper, even as we wonder what it is that makes him loathe Ruth on sight.

The relationship is a standoff until they meet on Ruth’s irresponsible and not exactly moral terms, and even that doesn’t give the movie the lift we keep waiting for, the meaning it searches for or the heart it generally lacks.

Rating: unrated, alcohol abuse, suicide, profanity

And Charlotte Rampling, George Ferrier, Edith Poor and Marton Csokas.

Credits: Scripted and directed by Matthew J. Saville. A Greenwich release.

Running time: 1:34