Room

A24 Films
Rated R for language.
Running time: 118 minutes.
Four stars out of four.

This is one of those situations in which mere words seem insufficient in describing a film’s profoundly moving power.

I can tell you this much, plainly and without shame: I sobbed throughout “Room,” about a mother and her 5-year-old son trapped inside a sparsely furnished, 10-by-10-foot space, and I started doing so long before the story turned truly harrowing. And afterward, I walked home from the screening room — 2.87 miles to be exact, I mapped it — to process my feelings. Did director Lenny Abrahamson’s film wreck me because it’s truly great, or because I also have a 5-year-old boy and motherhood has, as I’d long feared, turned me irreparably soft?

“Room” is indeed that great — but I might also be a ninny. In its poetry and power, its intimate details and ambitious ideas, it’s simultaneously devastating and mesmerizing. The truth at its core, which Abrahamson achieves through pure and subtle observations, is what astonishes again and again. Within this nightmare scenario, a mother and child have crafted for themselves a tangible fairy-tale world. They refer to the small area they share as Room. The window above their heads is Skylight. Ma’s bad tooth is — appropriately and affectionately — Bad Tooth. The boy, Jack, regards them all as treasured friends. But an enemy also lurks: Old Nick (Sean Bridgers), the volatile, middle-aged man who put them there and makes frightening, nightly visits.

But despite the extreme events that led to their cramped captivity, there’s a realism to the relationship between Ma and Jack. They stick to a relatable routine — every minute matters, every day matters. They have a comfortable shorthand, the result of spending every single moment together. They make the most with what they have. They take care of each other.

Every parent will recognize himself or herself in Brie Larson’s Ma: She’s proud of her boy when he figures something out and frustrated with herself when she snaps at him too quickly. She answers his increasingly probing questions with patience and tries to protect him as long as she can. She’s a great mother, even though she didn’t choose to be one. It’s all there on the page in Emma Donaghue’s elegantly efficient screenplay, which she adapted from her best-selling novel. But the abidingly authentic performances from Larson and young Jacob Tremblay are what bring these words vividly to life.

If you saw Larson in her first, real starring role in the criminally under-seen “Short Term 12,” or in standout supporting parts in films like “The Spectacular Now” or “Trainwreck” or the Showtime series “United States of Tara,” you knew what she could do — you knew of her naturalism and her presence. Here, she conveys so much with just her posture, with the slightest glance. There’s nothing showy about her performance and yet you can’t take your eyes off her. She just never hits a false note (and rarely does the film as a whole). And she has a deeply believable chemistry with Tremblay, who’s excellent in a complicated, demanding role. There’s nothing cutesy about him — there’s not the timiest whiff of child-star precociousness. He is just totally in the moment all the time. He’s a tremendous find.

You may have noticed that I haven’t written much about plot yet, and that’s intentional. Yes, the trailers and even the signature image on the posters reveal that eventually, Ma (who’s only 24 and whose real name is Joy) and Jack escape their prison in a scene of meticulous timing and breathtaking suspense. They return to the outside world, something Jack only knew of from images on a beat-up television set and glimmers from the skylight, but for a while it’s more of a place of obstacles than opportunities.

The second half might seem more ordinary than the first, perhaps because it’s a world we actually know and one that seems safe. But it’s fraught with its own perils, both externally and internally, and how Joy and Jack navigate them together gives this section of “Room” an even larger kind of heart and even a sense of hope. They get help from a superb supporting cast, led by Joan Allen as Joy’s relieved mother and Tom McCamus as her stepdad, who forges his own lovely, unexpected connection with Jack. (William H. Macy, as her detached father, might have gotten more to do but that’s a minor quibble.)

And that’s all I want to say about “Room,” for now, at least. Please go experience it for yourself and let the emotions and revelations wash over you — and then come back and let me know that I’m not alone in being reduced to a puddle.