We know D.C. Get our free newsletter to stay in the know.

There’s a small gut-punch at the beginning of Puzzle. Agnes, a housewife and mother of two college-age boys, is cleaning her home and decorating for a birthday party. Later, the house is packed, and when Agnes leaves the kitchen to serve hors d’oeuvres and pick up the pieces of a broken plate, she asks her husband, Louie, if he’s having a good time. He says he is and thanks her. Then it’s time for cake.

It’s Agnes’ birthday.

Agnes is played by Kelly MacDonald, perhaps best known for Boardwalk Empire. Seeing her as a film lead—and not just a leading lady, but a lead lead—is a welcome surprise after two decades of supporting roles, and her Agnes is both sympathetic and terribly likable as an introverted woman who has long put her needs aside. When a birthday present of a jigsaw puzzle leads to her discovery that she has a knack, it gives her a glimpse of the world she’s been missing while being subservient to her husband (David Denman) and sons (Austin Abrams and Bubba Weiler).

Agnes’ satisfaction after she completes that 1,000-piece puzzle prompts her to buy another. In the store, she sees an ad from someone searching for a puzzle partner and texts the number (never mind that she’s used cellphones only for emergencies before). The searcher is Robert (Irrfan Khan), a wealthy New York inventor who needs a partner not for leisure but for a tournament, a fact that catches Agnes off guard. But she’s into it: Yes, she will travel from her working-class suburb by train twice a week to practice. No, she won’t tell her family. Are you kidding?

Puzzle is a remake of an Argentine film, adapted by Oren Moverman (Love & Mercy, The Messenger) and Polly Mann (a first-time scripter) and directed by Marc Turtletaub. The filmmakers get most everything right; this is a sensitive portrayal of a sheltered, sensitive woman. Most everything, that is: There are some details that don’t add up, such as why so many people are at Agnes’ birthday party if she rarely leaves her house, or how she can easily navigate New York if she doesn’t even know where to buy a puzzle (she asks the gift-giver). And would a mom really not know where to buy a puzzle?

Denman and Khan join Macdonald in giving nuanced performances that are at once funny and heartbreaking—in other words, human. Denman’s Louie isn’t a one-note jerk who freaks out when, for example, Agnes says she’s going to help her hobbled aunt a couple times a week; at times he’s tender, and you can see why Agnes grows conflicted about her imperfect marriage after becoming close to Robert. Khan, meanwhile, is a walking (but frequently joking) wound as the competitive hobbyist whose wife left him. His other obsession is natural disasters and aching over the scores of people who lose their lives to them.

But it’s Macdonald’s show to steal. “I’m not comfortable, generally” her Agnes tells Robert when he says that she seems uncomfortable around him. She’s hesitant and kind, the type to repeatedly apologize when she cuts off a car even though the driver obviously can’t hear her. She nearly apologizes for her existence. But Agnes quickly grows a spine, emboldened by Robert’s interest in her and, more, her realization that she’s very good at something besides housework.

Like the character, Puzzle is refreshing, predominantly because it doesn’t follow the practicing-for-a-championship storyline that so many films about competing do. But it’s just as satisfying to watch this shy puzzler figure out that the life she’s known for so long doesn’t quite fit.

Puzzle opens Friday at Angelika Mosaic.