At points throughout Benedikt Erlingsson’s Woman at War, Halla (Halldóra Geirharðsdóttir) passes by a small band of musicians playing the very same ponderous music that scores her exploits. The transition from diegetic (on-screen and part of the action) to non-diegetic music is seamless — at one point, one of the band members simply pops up in Halla’s house, playing the piano as she processes a life-altering phone call, and at another, a small chorus of women appears. At times, they frown, stare, or smile, characters in their own right, or a twist on the Greek chorus. They’re unexplained, strange, and charming — not unlike the film itself.

By day, Halla works as a choir conductor, biking around town and returning home at the end of the day to a cute apartment decked out with (tellingly) portraits of Mahatma Gandhi and Nelson Mandela. By night (or, well, whenever she’s not at choir practice), she takes up the mantle of “the Mountain Woman,” disrupting the operations of the nearby Rio Tinto aluminum plant — a large-scale polluter of the local ecosystem — by damaging pylons and wires and thereby shutting down the plant’s power. She’s a modern superhero: she’s fighting for what she believes to be right, and does so with a secret identity and a skill set (proficiency with a bow and arrow, general sabotage know-how) that can’t be said to be universal.

The film opens in the middle of one of Halla’s shutdowns. Despite being a relatively significant act of illegal activism, it manages to keep from sliding into “gritty” territory by virtue of the band and Halla’s simple, earnest dedication to her cause. The sequence effortlessly establishes character motivation and context without relying on an excess of exposition. A brief exchange with a nearby farmer, Sveinbjörn (Jóhann Sigurðarson), provides context for her actions without getting bogged down — soon enough, they’re discussing when she’ll be able to return the car she’s borrowing from him, and whether or not they might share some ancestry.

It makes the transition into her civilian life funnier to watch, as her seriousness seamlessly shifts to sunniness (that could easily be mistaken for harmlessness) as she leads her choir in song. The two faces she presents to the world may seem vastly different, but they’re not actually so far apart.

That facility becomes especially important as a years-old application to adopt is suddenly approved. Halla wants to be a mother, and the idea that a little girl might be relying on her changes how she views the consequences on her actions; if she’s caught and jailed, then she won’t be able to go through with the adoption.

The individual elements of the story — including an identical twin sister (also played by Geirharðsdóttir) who pursues inner, spiritual fulfillment and finds the Mountain Woman’s actions destructive — may make the ending a little predictable, but they’re so rarely found in the same piece that it hardly matters. The subtle way that the film tackles environmental activism and anxieties about motherhood, punctuated by Wes Anderson-like flights of fancy, without losing either gravity or its lightness of touch is a remarkable accomplishment; Woman at War is a smart delight.

It’s at least in part due to the way Erlingsson seems to savor the smallest human interactions — the back and forth between Halla and Sveinbjörn, for instance, which grows warmer as the film progresses — consequently turning what could be an unwieldy, overambitious piece into a compelling, eminently relatable movie. Geirharðsdóttir’s casting is a home run in this respect: she projects a perfect sense of strength and vulnerability, making it easy to believe that the same woman who’d hide in a goat carcass and single-handedly pull down a pylon would also cheerfully dish with her chorus group. (Erlingsson touches upon such stereotyping by showing the repeated arrests of a hapless male Spanish-speaking tourist, played by Juan Camillo Roman Estrada, while Halla goes unbothered.)

Halla is also a remarkable heroine for being of an age (Geirharðsdóttir is 50) when female characters are generally relegated to either staying home — or being markedly kooky when they decide to take action. There’s nothing in Woman at War that treats Halla as being exotic or an anomaly, and there’s no need for her to sacrifice her femininity for it; there’s nothing unusual about the fact that Halla has chosen to take control of her own story. It’s treated as matter-of-fact that she should be a sort of superhero — why shouldn’t she be?

There’s a sense of literalism that winds in and out of the film, as Halla is more than once seen lying on the ground, seeming to breathe in the earth, but it works in tandem with the use of on-screen musicians and other unbelievable moments that, in Erlingsson’s hands, feel perfectly true to life. Halla’s struggle may be against heavy industry; her film is a vibrant, life-affirming kind of green.