‘The Crown’s’ Kirby enters a new realm of heartbreak

Let’s begin this year with a renewed appreciation for the magicians we call actors. A good actor knows a hundred ways to tell the truth and provide what’s missing, or authenticate what’s overstated or phony. “Pieces of a Woman” illustrates dozens of those ways.

As a woman coping with staggering grief and loss, Vanessa Kirby is excellent. Kirby’s best known as Princess Margaret in the first two seasons of “The Crown,” and she brought her silky, formidable stage technique honed on Shakespeare and Chekhov to a global phenomenon. Moral: Doing a lot of difficult, beautiful plays before focusing on smaller canvases makes for the best kind of training.

The emotional stakes run sky high in “Pieces of a Woman.” Determined to deliver her baby at their Boston-area home with a midwife, Martha (Kirby) and her partner Sean (Shia LaBeouf ) have been prepping the nursery for months. Sean is six years sober. Martha has a way of cloaking her hormones and emotions as a coping mechanism. Martha’s imperious, controlling mother, Elizabeth (Ellen Burstyn), a Holocaust survivor, disapproves of Sean, a rough-and-tumble construction foreman.

Much of the first half-hour of “Pieces of a Woman” detail the excruciating events of the birth itself, aided by a last-minute substitute midwife (Molly Parker). Director Kornél Mundruczó’s camera follows Martha, Sean and the midwife around the house in a carefully staged 25-minute endurance test. Martha’s resulting shock and loss points to what this film is truly about: loneliness, in extremis.

Martha and Sean, already on somewhat thin ice, push each other way. Elizabeth and Sean focus their energies on dragging the midwife into court. Sean seeks solace in his old, addictive crutches and an affair, while Martha slowly comes to a realization the audience can all too easily anticipate.

The script comes from a play by Kata Wéber, based on her own, wrenching experience. Moment to moment, Kirby creates a whole character out of small, often colliding details, and she’s remarkable at showing us someone keeping it together while falling apart on the inside. LaBeouf ’s character is pretty exhausting, both as written and played.

This is difficult to say, given the trauma out of which it was born, but “Pieces of a Woman” is well-acted while also being pretty shameless (when it’s not merely contrived) in its storytelling tactics. There’s no dramatic ambiguity regarding the midwife’s culpability or lack thereof, so Martha’s “journey” feels false. The husband’s affair, with a strategically important supporting character, doesn’t wash.

Burstyn manages her centerpiece monologue about a terrifying infancy hiding from the Nazis supremely well, but it arrives on a tray like a big speech in a slightly stiff theatrical enterprise. The metaphors arrive on their own trays, from the bridge-building motif, literal and figurative, to the ever-present blood-red tones in the costuming and production design.

Grief is tough, because it defines so much of our lives, and it’s harder than hell to dramatically honor. Why, for example, does “Manchester by the Sea” work so well, while HBO’s recent “This Much I Know is True” struggle and strain every step of the way, even with tip-top actors? In “‘Pieces of a Woman” Kirby never seems to be building up artificial climaxes or big reveals; she works on a quieter, truer level. Too much going on

her ends up working against her.

MPAA rating: R (for language, sexual content, graphic nudity and brief drug use)

Running time: 2:08 Available: on Netflix

BENJAMIN LOEB/NETFLIX Vanessa Kirby loses a baby and her relationship starts to fall apart in “Pieces of a Woman.”