Irish director Lenny Abrahamson puts a lot of devastation on the screen in his remarkable film Room. But, for me, the picture's resonating power lies in what is not told and the deep sadness that comes from trying to assemble the pieces. Abrahamson has filmed fellow Irelander Emma Donoghue's screenplay of her bestselling novel of the same name. She tells the story of a young mother (Brie Larson), known only as Ma, and her 5-year-old son (Jacob Tremblay) who are captives of a terrifying man called Old Nick (Sean Bridgers). Ma has been locked in Old Nick's garden shed for seven years; her son, all of his life. The circumstances of the boy's birth, how he and his mother have been sustained, how they came to create the worlds that keep them sane are weighty imponderables. Abrahamson has crafted the first half of the film so carefully that these claustrophobic confines never feel oppressive, primarily because Jack's innocent wonder about life, as stiflingly artificial as it is, is so genuine and marvelous -- and, yes, tragic. When Ma finally decides they have to escape, the viewer is torn because in doing so she must dismantle Jack's world. The scene of his tearful rejection of her talk of "the world" is nearly more than one can stand. But escape they must and do and that sequence is wrenching and terrifying. The two are finally reunited with family (Joan Allen, William H. Macy and Tom McCamus) but this new chapter feels as perilous for Jack and Ma as their imprisonment had been. Such a beautiful, heartbreaking story.