After Collette (Andrea Riseborough), right, gets arrested after placing a bomb on the subway, Mac (Clive Owen) pressures her into becoming an MI5 spy. (Magnolia Pictures)

The hopelessness of the self-perpetuating cycle of violence that characterized the strife in Northern Ireland in the 1990s also characterizes “Shadow Dancer,” a moving if also somewhat deflated thriller set in that era. It’s a mostly gripping tale with a nice twist. But the story — adapted by Tom Bradby from his 1998 novel and directed by James Marsh — is delivered with something akin to resignation.

It doesn’t make it slack or lazy, but it does give it the ring of ugly truth.

Maybe that’s because Marsh cut his teeth on documentaries. He’s the director of such acclaimed films as “Man on Wire” and “Project Nim.” Just as likely, it’s thanks to the performances of Clive Owen and Andrea Riseborough, who play a seasoned English MI5 agent and a reluctant Irish terrorist, respectively, caught up in a fatalistic, and mutually destructive, bargain. They’re both deeply compelling actors.

Riseborough plays Collette, a young Irish Republican Army soldier who first meets Mac (Owen) when she’s arrested after almost placing a bomb on the London subway.

The fact that she panicked and didn’t set the detonator, abandoning the bomb in a stairwell, doesn’t exonerate Collette. But it does suggest to Mac that she just might be ambivalent enough about the business to be recruited as a spy.

Is it ambivalence or desperation? Mac implies that if she doesn’t accept the deal, she’ll be thrown in jail, never to see her young son again.

So Collette accepts, and it’s back to Belfast she goes, where she begins delivering intelligence to Mac — via a series of dangerous meetings and surreptitious phone calls — about the activities of Kevin (David Wilmot), the ruthless and highly secretive local IRA leader, as well as her two brothers, who work for him.

Collette may never have set off that detonator at the beginning of the film, but director Marsh clearly has. There’s an ominous sense of a ticking time bomb throughout the film, reminding you that someone’s going to get hurt. We just don’t know who or when.

Collette almost immediately draws Kevin’s suspicions after she tips Mac about a planned IRA hit that only she and her brother (Domhnall Gleeson) knew about. Mac, for his part, finds himself developing feelings for Collette, especially after he learns that his supervisor (Gillian Anderson) won’t let Mac pull his young recruit out of her assignment, even after Collette has made good on her end of the bargain.

If it sounds like something rotten is afoot, you’re right. Collette is not the only character navigating a gray moral area.

Shadow Dancer” is a thriller, but it’s far from a simplistic one. Who, for instance, are the good guys? A prologue shows Collette’s radicalization as a child, after witnessing an act of terrible violence. But does that experience justify killing innocent people in retaliation? Mac might be the closest thing to a hero, but he’s also tainted by working with people who clearly aren’t so idealistic.

Ultimately, “Shadow Dancer” delivers on its threat of tragedy. The question that the filmmakers are most interested in isn’t who gets punished in the end, but whether they deserve it.


R. At Landmark’s E Street Cinema. Contains violence and obscenity. 101 minutes.