Rachel Singer (Jessica Chastain) is a Mossad agent, and her assignment in 1966 has in an especially horrific situation. In order to confirm the identity of a former Nazi now working as an obstetrician in East Berlin, she’s pretending to be a patient. This means, of course, that as she’s snapping pictures of him using a secret mini-camera hidden in her necklace, she’s lying back on an exam table, feet in stirrups and legs spread wide.

The scene is one of the most galling in The Debt, and it resonates even beyond the obvious grim relationship it sets up between killer and victim, or rather, killer and monster Dieter Vogel (Jesper Christensen), also known as the Butcher of Birkenau, where he tortured prisoners under the guise of conducting “medical experiments.” As she looks at him from her awkward and achingly vulnerable perspective on the table, he seems grotesque, his aging face especially ugly and his threat perpetual. This guy deserves everything he’s going to get.

The Debt being a political thriller (in fact, a remake of 2007 Israeli film directed by Assaf Bernstein), you won’t be surprised to hear that what Vogel is supposed to “get,” the carefully orchestrated assassination by Rachel and her fellow Mossad agents, does go precisely as they plan. Indeed, the film is more about how things go wrong in a world where proper orders of all kinds—legal, moral, emotional—seem easy to see. It sets up and then tracks a variety of debts, owed and felt and paid, by a range of individuals and collectives. If Vogel—standing in for “Nazis—sets evidently egregious these debts in motion, his perverse ethical compass makes extracting payment from him difficult. Thus, the film suggests, the Mossad claims its moral imperative, its commitment to making the world right through brutal vengeance.

But the film also illustrates the tolls that such violence takes on the Mossad agents, Rachel along with David (Sam Worthington) and Stephan (Marton Csokas). When they first meet for their mission in East Berlin, they’re youthful and vibrant, sure their cause is just and their consciences are clear. Rachel walks across the border from the West, her documents checked by armed guards, and smiles beautifully as she first sees her contact, David, whom she’s actually seeing for the first time but greets as if he’s her much-missed husband. They play their roles perfectly, acting the young, hopeful married couple, eager to start a family, even as they also plot the assassination.

Their youth and idealism are also real, of course, for otherwise they wouldn’t be agents with such an elite and ultra-dedicated organization. Rachel embodies one sort of hope, associated with a future where evil is vanquished. David is more fixed on the past, having lost his parents in the Holocaust and determined to assert a balance of atrocities. This is impossible of course, and so he’s writhing inside, a sort of convolution that Worthington only approximates. At the same time, and as Rachel is—too predictably—attracted to the sensitive, pained David, they’re both observed by Stephan, more intense and more convinced that he knows exactly what he wants. And so, even as they try to keep focused on the mission, the threesome engages in an intrigue of sexual, not quite romantic, dimensions.

You know most of this, and guess at the specifics, much earlier in the film, as it actually opens when the agents are old, that is, played by Helen Mirren, Ciarán Hinds (David), and Tom Wilkinson (Stephan). Rachel and Stephan are in this present, 1997, estranged but proud parents of Sarah (Romi Aboulafia), who has just published a book about their exploits. As the author and her parents are feted in Tel Aviv, Rachel reads a passage from Sarah’s version of events, a story she’s heard since she was a child, a story enshrined in Israeli history, wherein Vogel, imprisoned by the three courageous agents, tries to escape, bestows on Rachel a facial scar that she bears to this day, and is then killed, rather sensationally.

As Rachel reads, the film cuts back in time to illustrate the event, all shadows and pounding soundtrack. By the time the scene returns to old Rachel, her face drawn and quite un-thrilled at the applause she receives from around the fancy party table, you have a sense that something isn’t exactly right. The tension between her and Stephan is noticeable as they glare at one another over the white tablecloth, and oh yes, you’ve also seen Stephan and David have rather a terrible encounter just before, during which David has decided to kill himself instead of going along with Stephan to the celebration.

As the film unpacks these many layers of debts and expectation, it keeps something of a focus on Rachel, whose regrets seem most visible. In part this is a function of her scar—so metaphorical as well as physical—but it’s also her function as the film’s girl, torn between two manifestly different men, essentially and too apparently embodying her emotional and moral struggles. Alas, the movie is increasingly unsubtle as it reveals the multiple truths about what happened back in East Berlin. No surprise, the captured Vogel is hideous, his face bruised and misshapen as he taunts his unprepared captors, especially as he names and mocks the stressful triangle they’ve conjured. It’s as if his being a Nazi isn’t bad enough: now he must also goad them into hating him personally, his gruesome personal incarnation of evil, in the film’s estimation, one definition of a Nazi anyway.

That it’s left to Mirren’s Rachel, in the end, to make the men’s accumulated mess right, is both weird and expected. That she becomes an awesome action hero (as if she’s been reteamed with Bruce Willis) is clumsy, as is the elaborate action she commits. And yes, she’s also a good mother (even if she has based her life post-East Berlin on a lie), an idea that Stephan, so troubled and troubling, actually uses against her. The debts can never be quite repaid. In delivering on its “thriller” promises, the film pretends at least one of them might be.