Available on DVD: “Beginners”

Christopher Plummer and Ewan McGregor in Beginners

How often do you see a story about a grumpy young man and his frisky father? Beginners, Mike Mills’ captivating film, centers on an emo son, his buoyant dad, their romantic partners, and a most philosophical Jack Russell terrier. It’s a movie about untangling roots in order to grow.

This is the challenge for the melancholy Oliver (Ewan McGregor), who at 38 is stunted, a human bonsai. Since the death of Oliver’s mother, his vivacious father, Hal (Christopher Plummer), has come out of the closet and into his own. Hal, a museum curator, thrives in the sunshine of attention. This has the effect of leaving Oliver, a graphic artist with a pronounced charisma deficit, in the shadow of his own introversion.

Mills tells their story in a chatty, nonchronological fashion. As with Annie Hall and (500) Days of Summer, we know from the top that certain relationships are terminal (Hal has cancer). Mills’ tone nicely balances the woeful with the whimsical by pairing McEwan’s rueful performance with Plummer’s raucous one.

The film chronicles the parallel stories of the father’s and son’s love affairs. The Cupid in both cases is Arthur, a no-nonsense Jack Russell who knows that if the lives of his successive owners improve, so will his.(Arthur communicates to Oliver via subtitles, explaining that Jack Russells were bred to hunt foxes and making Oliver wonder what he was bred for.)

What’s refreshing about Beginners is its sympathy for all of its characters, which translates into the characters’ sympathy for each other.

Oliver has mixed feelings about Dad. Hal’s longtime secret clearly created intimacy issues for his wife (played in flashbacks by the spirited Mary Page Keller) and his son.

Yet Oliver compassionately reconstructs the family narrative from his father’s perspective. This is what the sun looked like in 1955, he thinks, looking at light-filled photos of the year his parents met, a time when popular images of domestic happiness were strictly heterosexual.

Hal’s reticence to come out during Oliver’s formative years no doubt seeded the son’s attachment issues. How does the son who grew up without evidence of his parents’ love know how to express love?

And yet the father’s exuberant swan dive into outness, his commitment to the shaggy Andy (Goran Visnjic), his beginning again, inspire the son.

Oliver goes to a costume party dressed as Freud. There he meets Anna (Mélanie Laurent), whom he tentatively courts. (Why Mills named the female character Anna, possibly after Freud’s child-psychologist daughter, is the subject for its own disquisition.) Laurent is as wistful, wide-eyed, quirky, and tentative as her suitor.

Mills, whose previous feature was the underseen Thumbsucker, began his career as a graphic designer, and his compositions are sharp and well-outlined — all the better to contemplate characters evolving from fuzzy to defined.

He gets lively performances from his leads and from Cosmo, the supremely self-contained dog who plays Arthur. In his twilight years, Plummer shows all the colors of the emotional spectrum. Nearing his middle years, McEwan quietly is becoming the most relatable Everyman, one whose matter-of-factness in exposing human frailty is one of his greatest strengths.