If “Captain Marvel” has whetted your appetite for a female superhero who pulls up her sleeves and gets to work, check out “Woman at War.”

As this intriguing, visually stunning movie opens, Halla (Halldóra Geirharðsdóttir) is in the mossy rural Icelandic highlands, shooting an arrow across an array of utility towers, her goal remaining elusive in a mostly silent sequence. She doesn’t speak until she encounters a farmer who agrees to help her in what turns out to be her single-minded quest: to protest the government’s cooperation with polluting corporations, in this case an aluminum smelter.

Back in Reykjavik, Halla is a choir director whose secret life she shares with only a couple of accomplices. She has posters of Mahatma Gandhi and Nelson Mandela hanging in her sunny middle-class house, suggesting bourgeois dilettantism or self-sacrificing commitment.

Benedikt Erlingsson, who wrote and directed the dramatic thriller, doesn’t force viewers into one camp or another.

As Halla’s actions become riskier and more audacious — made even more questionable by an unexpected development in her personal life — a film that could be a reflexive celebration of radical political action instead becomes a thoughtful meditation on the ethics of extremism, limits of nonviolence and appropriate response to global threats that aren’t just environmental or economic but existential.

It has all the contours of a taut, paranoid thriller, if you can imagine that set within the tidy, brightly lit environs of Iceland. The film’s serious subject matter is undercut by a jaunty score, performed on screen by a trio of musicians who act as a silent Greek chorus and window into Halla’s psyche. When three more musicians show up — traditionally costumed women singing Ukrainian folk songs — her internal struggle between destructive and nurturing impulses is laid bare with even more captivating clarity.

A movie as intensely subjective as this had better have an actress deserving of unwavering attention, and Erlingsson has found her in Geirharðsdóttir, who proves to be supremely at ease with the physical demands of the film and its trickier internal journeys. She is a figure some will see as brave and heroic and others will see as woefully ­misguided.

The movie might have set itself up as a contemporary fairy tale, especially by way of its playful staging. But it’s also about very real questions having to do with globalization, ecological degradation and the people we chronically dismiss, underestimate and ignore.

As Halla continues to tilt at her modern-day windmills, she grows closer and closer to the Earth, covering herself in mud and soil, ultimately becoming one with the thing she’s trying to save.

By the time “Woman at War” concludes, what could be perceived as a happy ending also carries with it a Cassandra-like warning and a bittersweet note of futility. It’s a reflection of Erlingsson’s confidence, in his audience and his own filmmaking skills, that he leaves the final interpretation up to us.