Jake Gyllenhaal is the star of Stronger, David Gordon Green’s film about Boston Marathon bombing survivor Jeff Bauman. He portrays the trauma of losing both lower legs in the blast with startling frankness — the post-traumatic stress, the wait to heal, the slow and difficult process of rehabilitation, and what it’s like to contend with both depression and being made into an unwilling national symbol. Gyllenhaal may get an Oscar nomination for his work in the film, and that wouldn’t be a bad thing. But Tatiana Maslany is the reason the movie works as well as it does — as more than a chronicle of suffering and recovery in the wake of an act of terrorism.

It’s not just Maslany’s performance that’s remarkable, though she’s genuinely great as a woman trying to figure out if she can make a life with someone who seems, at times, unwilling to make a life for himself. The prominence given to her character, Erin Hurley, Bauman’s then on-and-off girlfriend, eventual spouse, and now ex-wife (a part of their relationship that doesn’t make it onscreen), is noteworthy in itself. Stronger, adapted from Bauman’s memoir and written by John Pollono, is as much Erin’s story as it is Jeff’s, and is a far better movie for it. More than anything, it’s a love story, and a difficult, intense one that’s not just about two people contending with catastrophe, but about how catastrophe doesn’t erase relationship problems that were already there.

What it’s not is an attempt to capitalize on still fresh distress, in that strange Hollywood tendency to put rough recent history onscreen as if reenactments of tragedies justify themselves, nothing more needing to be said. Stronger is the second Boston Marathon bombing movie to come out in the less than five years since the incident happened — not a giant span of time in which to accommodate two major movies featuring two big stars. It arrives less than a year after Mark Wahlberg’s Patriots Day, one of two ripped-from-the-headlines features Wahlberg and director Peter Berg released in 2016, and the kind of film that did solemnly serve up the attack and its aftermath as if it were a kind of public service.

To its credit, Patriots Day was a relatively restrained affair that resisted the urge to sensationalize. But it really didn’t need to, given how it jabbed at healing wounds in the name of prestige cinema, casting Wahlberg as a fictional police sergeant who ended up conveniently central to the all major events surrounding the bombing, its aftermath, and the subsequent manhunt. It was a movie about an act of violence, while Stronger is a movie about people whose lives were spun out by that act of violence, and who struggle to move forward in its wake. Stronger is, in some ways, the opposite of Patriots Day in its deep sense of humanity, its focus on recovery rather than revenge, and its interest in contending with the public’s habit of neatening complicated narratives into inspirational fables.

And Jeff and Erin’s story is complicated. They are, at the start of the film, a month into their latest breakup. A chance run-in at a bar makes how much they still like each other clear, as well as Erin’s reasons for pulling away. While Jeff is sweet and smitten, he’s also flaky, immature, tending to let his protective, raucous family dictate the terms of his life, including the place his outsider sometimes-girlfriend has in it. He’s a little too comfortable where he is, and, as Erin puts it, he doesn’t show up, and it’s to prove that he’s changed that he turns up as promised on the day she’s running in the marathon, staking out a spot by the finish line to cheer her on. When the bombing occurs, their nebulous relationship is made even more so by the guilt Erin knows she shouldn’t feel but can’t entirely shake off.

Jeff endures something terrible, and Gyllenhaal, looking especially boyish, transmits his shock and anguish so believably it’s sometimes hard to watch. But Stronger also stays alongside Erin as she sits in the hospital next to his family, distraught and uncertain, quiet in the corner while they grieve out loud. In those early sequences, Stronger sometimes unexpectedly recalls another, very different film from this year, The Big Sick. It, too, captures how it feels to be unsure of where you belong in someone else’s calamity, especially when romantic ties can be defined along so much more of a spectrum than familial ones. Erin lingers there by Jeff’s side, visiting and accompanying him through harrowing medical procedures. She’s there right up until he’s brought home to the apartment he shares with his mother (Miranda Richardson), to prepare for rehabilitation and a readjustment to an altered life that he dismisses her from. And she, having no excuse to stay, leaves.

The movie suffers whenever Erin’s not onscreen, not just because of how painstakingly present Maslany is in the role, but because as a solo show, Stronger can’t help but drift into the territory of so many past depictions of disability, in treating it as a kind of acting challenge, a technical feat. The film is careful and empathetic about Jeff’s experiences — how he contends with living in a space where the stairs, the hallways, and even the placement of a toilet paper roll in the bathroom no longer accommodate his body and mobility. There are rare moments when you’re reminded that you’re watching an able-bodied actor play a person with a disability, but they exist and are always uncomfortable. And all of them arise from scenes built around the idea of Jeff learning to overcome his disability, rather than exist with it.

Stronger is at its best when it’s a movie about allowing Jeff to live rather than needing him to triumph. Which means, at times, that he’s a jerk and a lousy partner, wallowing in self-pity and inertia, getting trashed with his hard-drinking mom or his friends from the neighborhood. The boldest thing Stronger does is trust enough in Maslany’s performance and in the writing of her character to allow Erin to do something that a lesser movie would never even attempt — to walk away, and not just once, when Jeff is ready to let himself go. When Stronger does find its way to a happy ending, it’s hard fought and hard won.

Gyllenhaal’s may be the showy part in Stronger, but Maslany’s is, in many ways, the more difficult one, and the one that affirms the movie’s subdued but undeniable worth as a relationship drama. When everyone is choosing to see Jeff as a heroic figurehead, an emblem of “Boston strong,” Erin looks as him as the flawed guy he’s always been. And Maslany exudes a heartbroken but confident certainty as her character calls him on his own shit, and grapples with whether they have a future together. It’s unbearably sad, and unbearably real.