The first half of this Irish-Canadian indie is so depressing I could barely stand it, but in the second half my emotional investment paid off handsomely. Loosely based on the Josef Fritzl case, it’s the story of a young woman (Brie Larson) who’s been kidnapped, held captive for seven years in a tiny room, and serially raped, which has left her with a five-year-old son (Jacob Tremblay). After they finally escape from this cloistered existence, finding shelter with the boy’s grandmother (Joan Allen), the young woman begins to struggle with post-traumatic stress while the boy tries to wrap his head around this thing called “the world.” Lenny Abrahamson—whose previous feature, Frank, also dealt with social dislocation—directed a script by Emma Donoghue, who adapted her own novel. With William H. Macy and Tom McCamus.