Charlotte Rampling in Juniper (Greenwich Entertainment)

Combining the well-worn genres of the coming-of-age and end-of-life stories, Matthew J. Saville’s writing and directing feature debut won’t win any awards for originality, but it’s well worth watching thanks to its balance of sentiment and sardonic humor, along with its two compelling lead performances.

Sam, a teenager reeling from his mother’s premature recent death, has just been expelled from boarding school and returns home. When his emotionally (and often physically) absent father, Robert, tells him his grandmother Ruth will be staying with them while she recovers from a fractured leg, Sam really doesn’t have any interest in dealing with an old woman he’s never met.

A retired war correspondent, Ruth is an ornery sort who doesn’t suffer fools gladly. She drinks a pitcher of gin like it’s water, daily, and starts to make Sam’s life hell by constantly ringing the bell for him to help her while she recuperates. Though he’s initially put off, that feeling evaporates (no surprise), and he comes to appreciate and grow fond of his lively alcoholic grandmother, who returns the favor by confiding in him, like revealing she never has told Robert who his father is. (Sam later comes to think that it’s because she doesn’t know.)

Plotwise, Juniper is pat and predictable—there are moments when you’ll guess what will be said or happen next—but Saville is far more interested in developing this offbeat but vital relationship. Ruth is actually impressed that Sam keeps returning to her, despite her selfishness and insolent behavior. “At least you’re a fighter,” she tells him.

Sam and Robert’s relationship is explored in less detail—Sam is furious that Robert doesn’t seem to miss his mother like he does, especially after a young woman answers the phone when he calls Robert. A certain but uneasy reproachment occurs, after Sam realizes the hell Ruth must have put Robert through while his dad was growing up. As Robert, Marton Csokas considerably enlivens what is, as written, a stock part.

There’s a fourth character, Sarah, Ruth’s young and attractive nurse, winningly played by Edith Poor. It’s to Saville’s credit that he ignores the obvious route (the one time the predictable doesn’t happen) and doesn’t have Sarah and Sam hook up. Hints are dropped—twice Sarah walks in at inappropriate times, when Sam is masturbating and while he and Ruth are discussing whether he’s a virgin—but Saville happily has them resist the temptation.

Shot in the verdant pastures of New Zealand, Juniper (an apt title since juniper berries provide the liquor’s flavor) remains naturalistic except for one obviously symbolic white horse that runs through the greenery at the beginning and then returns in the most misguided scene, when Sam, in the midst of a self-destructive impulse, stumbles around and encounters the majestic animal.

Despite the missteps, Saville has written an emotionally direct script loosely based on his own experiences that is enlivened by his stars. George Ferrier, as Sam, makes his film debut with an incisive, uncompromising portrait of teenage angst that is also quite funny. Then there’s Charlotte Rampling, who has made a cottage industry out of playing cool, intelligent, slightly distant women, from Woody Allen’s Stardust Memories to François Ozon’s Swimming Pool, to name two.

Rampling’s Ruth forcefully rages against the dying of the light, and is noticeably relieved that her grandson might turn out to be all she had hoped her son would be, even after Sam is tossed out of boarding school again. The gleam in Rampling’s eye when Ruth says that she’s proud of him, that “all the best people get expelled,” is simply priceless.