In a summer of apocalyptic movie behemoths, it’s almost shocking to stumble on a modest treat like “Shadow Dancer,’’ a drama set during the Irish Troubles of the early 1990s. As directed by James Marsh, a very good documentarian (“Man on Wire,’’ “Project Nim’’) making one of his occasional sallies into fiction, the movie’s a tautly minimalist, occasionally generic study of betrayal and family ties.
A Belfast prelude sets the stage: A girl (Maria Laird) sends her little brother on an errand she’s been charged with, and he’s killed in the crossfire between Catholic and Protestant. The cycles of guilt and revenge are endless and endlessly renewed. Twenty years later the girl has grown into Collette (Andrea Riseborough), a single mother and reluctant accomplice in the IRA wars fought by her surviving brothers, Gerry (Aiden Gillen) and Connor (Domhnall Gleeson). During a halfhearted bombing mission to London — she leaves the device, unset, on a stairwell in the Underground — Collette is grabbed by MI5 and forced to become a mole in the family business.
Her agency contact is Mac (Clive Owen), as given to paranoid brooding as Collette, and why shouldn’t he be, since his boss (Gillian Anderson, chicly and unrecognizably British) is playing her own long game and leaving Mac out of the meetings. “Shadow Dancer’’ plays out in a landscape of fiercely repressed passions: The attraction the two leads can’t begin to express for each other, the rage of Gerry and Connor toward both the British oppressors and the IRA higher-ups who are suddenly talking peace.
Working from Tom Bradby’s adaptation of his 1998 novel, Marsh directs this drama as a series of small, sharp gestures, and in Riseborough he has an actress who knows how to do more with less. A British up-and-comer who has made a few Hollywood forays (“Oblivion,’’ “Disconnect’’) and was Wallis Simpson in Madonna’s “W.E.,’’ she plays Collette with deglamorized realism and a tension that doesn’t let up. Her character is never not watched — by MI5, by her brothers, by Kevin, the snakelike leader of the local IRA cell (David Wilmot) — and the birdlike Riseborough trembles with the fury of a woman who’s tired of playing the victim.
“Shadow Dancer’’ assumes a familiarity with the history and politics of Northern Ireland that Stateside audiences may not share, and it keeps its emotions so tightly in check that it risks seeming inconsequential. On one hand, Marsh overplays the symbolism: Collette wears a red coat when she’s working for MI5 and a blue coat when she’s back in the fold. On the other hand, he can direct a funeral procession, the Catholic mourners seething against a wall of British soldiers, so that the cobblestones feel primed to explode.
In this world, death is as constantly close as the unrolled plastic sheet in the next room when a suspicious Kevin grills Collette. As for love, it doesn’t stand a chance. “Shadow Dancer’’ is so flinty, so close-fisted that, ironically, it doesn’t linger in the memory. This is how it was, the movie says, and this is how it is, and only a naive spymaster would wish it otherwise.