Da'Vine Joy Randolph is an Oscar frontrunner for 'The Holdovers'

Our first clue that "The Holdovers" takes place in 1970 comes before it begins, with a vintage '70s rating certificate indicating that it's rated "R."

It's almost Christmas at a rural Massachusetts boarding school. A crotchety teacher named Paul (Paul Giamatti, reuniting with "Sideways" director Alexander Payne) is dismissing his "lazy, vulgar, rancid little philistine" students for the break while the school's cook, Mary (Da'Vine Joy Randolph) insists, "Everybody should be with their people on Christmas." Left unanswered by that statement is this question: Who are Paul and Mary's people?

They're the holdovers of the title, left on campus to make the best of the holidays with each other and with a troubled student, Angus (newcomer Dominic Sessa). It's a sad bunch. Paul is troubled by the missed opportunities that have him marooned at the school he once attended. Angus has been abandoned by his family. And Mary mourns her son, recently killed in the Vietnam War he could have avoided if opportunities for Black men weren't so limited in the America of 53 years ago.

Although there's sadness in "Holdovers," it's a sprightly, even hopeful film. That's because the characters are so distinctive and complicated. It's also because those three performers are magnificent. Sessa is a talent to watch and Giamatti instantly shows us that his character's gruff exterior hides an enormous heart. Paul, the movie hints, sees a young version of himself in Angus and would like to help him avoid pitfalls he fell into.

But it's Randolph — usually cast as a wise-cracking long-sufferer ("Only Murders in the Building" and "The Lost City") — who will blow you away. She creates a stunning portrait of someone who uses humor to hide the hole left in her heart by her son and by the racism and classism that held her back. "Rich and dumb," Mary comments wryly. "It's a popular combination around here."

The point, of course, is that these lonely people form a community. That's not a revolutionary idea but Payne makes the bittersweet movie special with just-right details and with a literary quality that makes me willing to bet money he's a fan of books such as "A Separate Peace" and "Franny and Zooey." One detail in particular — Paul's misaligned vision — is used exactly the way it would be in a novel, to reveal an important truth about the character ("The Holdovers" is not based on a book but feels like it is).

The key to "The Holdovers" is the modesty with which Payne — an Oscar winner for co-writing "The Descendants" and "Sideways" — imbues the film, never drawing attention to small touches that make it ring true. There's an homage to the 1970 drama "Five Easy Pieces," for instance, that you may or may not notice. And the camera could zoom in for a close-up when it's revealed that a neighbor on whom Paul has a crush already has a boyfriend. Instead, the moment feels more powerful because we note it sadly, in the background, just as Paul does.

"The Holdovers" is not huge or earthshaking but, in the way it recalls the character-based human dramas of the 1970s, it feels almost perfect.

'The Holdovers'

***½ out of 4 stars

Rated: R for strong language and drug use.

Where: In theaters.