‘Room’ harrowing, unforgettable

From the outset, “Room” doesn’t look like an easy sit, as critics say in the trade. Adapted from Emma Donoghue’s 2010 novel of the same name, this unsettling captivity narrative about a woman and her young son living in the forced intimacy of a 10-by-10-foot garden shed is no one’s idea of a feel-good story. Yet in the hands of the author - who wrote the screenplay - and Irish director Lenny Abrahamson, what could have been a lurid, opportunistic glimpse into the heart of darkness instead becomes a probing, extraordinarily tender portrait of maternal devotion and youthful resourcefulness. The most handy comparison for filmgoers may be the 1997 Holocaust parable “Life is Beautiful,” in which a father desperately tries to protect a child from the horrors of his world by infusing it with joy, resilience and enchantment.

By the time “Room” gets underway, 5-year-old Jack (Jacob Tremblay) has learned to provide that sense of wonder all on his own. His mother, Ma - played in a note-perfect performance by Brie Larson - was kidnapped as a teenager seven years earlier. Impregnated by her captor, she has been fiercely guarding her son’s innocence and well-being ever since, including when the man known only as Old Nick appears to demand sex in return for groceries and supplies. Ma makes sure that Jack is hidden in a cupboard for these encounters, which he only dimly understands from his dramatically circumscribed experience. His entire world consists of the things he can see and touch within the tiny environs of the shed, which, thanks to Ma and his own imagination, has taken on the parameters of a fairy-tale kingdom: Inanimate objects - a toilet, a television - for him have become cherished friends and confidantes.

Jack can’t comprehend a greater world outside Room, as he and Ma call their shared universe, until his fifth birthday, when Ma decides to tell him more about the troubling roots of their life together. Soon thereafter, “Room” involves incident and scope that would lose impact if they were described here. Suffice it to say that - after a somewhat clumsy and unconvincing bit of physical mechanics - the story takes a dramatic turn, during which their bond is both strengthened and tested to an unimaginable degree.

As wrenching as “Room” is, especially during its grim first hour, it contains an expansive sense of compassion and humanism thanks to the sensitive direction of Abrahamson, who directed the similarly themed “Frank” and a lovely short film called “Garage.” Working with cinematographer Danny Cohen and production designer Ethan Tobman, he builds a world for Ma and Jack that’s both painfully claustrophobic and improbably rich, as they strive to create meaning and beauty even in the midst of the untenable. When the story shifts gears, the production takes on similarly vivid contours, underlining the disorientation of stumbling upon a completely alien existence.

As well-tempered as Abrahamson’s choices are in “Room” - including the casting of such supporting players as Joan Allen and Matt Gordon - it derives its power from the extraordinary central performances of newcomer Tremblay and Larson, who delivered a similarly tough and vulnerable breakout performance in the 2013 drama “Short Term 12.” Here, she’s both ferocious and fragile, single-minded and at sea as she copes with irretrievable loss and the uncertain gift of a wide-open future.

For his part, Tremblay takes what could have been a cloying, too-winsome role - especially during his frequent voice-overs - and grounds it in quiet watchfulness that’s both sober and bracing. Despite its sensationalistic plot and physical and emotional extremes, “Room” winds up being a closely observed testament to what parents and children learn first-hand every day: the pride and pain of separation, and the discovery, empowerment and liberation to be found in simply growing up.