While domestic terrorism may be a popular trend in blockbuster films (I’m looking at you, Christopher Nolan), most films don’t leave the definition of terrorism up to the viewer and even less deal with eco-terrorism, a possibly waning but very much present form of terrorism in America.

This theme, almost entirely unrepresented on film, makes Zal Batmanglij’s The East a unique experience. When a business exploits the environment, damaging not only the land and animals but also people, what level of revenge is justifiable? This is the question on the minds of the East movement, who conduct elaborate payback schemes in the name of helpless.

While most of us probably wouldn’t join an eco-terrorist group and many probably wouldn’t even empathize with one, Batmanglij and co-writer/star Brit Marling have presented a pretty persuasive screenplay in The East. Marling plays Sarah, an overachiever who goes undercover for her private-sector company, hired by her boss (Patricia Clarkson) to infiltrate the East and not to “go soft.”

True Blood star Alexander Skarsgård leads the anarchist group as Benji, a brooding giant with excessively long, brown hair (that – praise a higher power – is cut off early in the film) who has Skarsgård’s trademark combination of stone-cold intimidation and puppy dog eyes. After some awkward first impressions, Skarsgård portrays Benji in such an ominous yet honest way that he becomes somewhat of an antihero.

Ellen Page plays Izzy, an aggressive, influential member of the group. Contrasting Benji’s enigmatic personality, Izzy is blatant and clear. She provides an anchor of normalcy to the group, a rag-tag group of loners with a common goal. The other members showcase compelling performances by supporting actors Toby Kebbell and Shiloh Fernandez – Doc and Luca – who inspire trust with their kindness and clear intellect.

Marling more than delivers as the lead, whose entire lifestyle is questioned as she spends more time with the East, inevitably growing attached (as Clarkson declares is bound to happen). Marling commands respect as Sarah, with radiant confidence and a compelling sense of self-assurance. While we don’t know much about Sarah (besides that her home life suffering from being a spy all the time and such), Marling establishes a deep sense of respect with her character.

Sarah believably adapts to her situation in the East, thanks to the script’s perfect pacing and the supporting cast’s convincing acting. The members of the group are revealed appropriately for the audience to adjust right with Sarah, as aspects of their personalities and motivations behind their crimes are revealed. As both the star and co-writer, Marling gets extra kudos for character development.

Through these characters, Batmanglij and Marling successfully blur the traditional line between who is the good guy and who is the bad guy. There are no clear villains, and all of the characters carry admirable intentions. Staunch stances change, ironclad rules bend, and the protagonist/antagonist formula is completely disregarded. The East is truly thought provoking for those who like their leads served morally gray.

For example, one of the first group-members introduced is Doc (Kebbell), the East’s resident healthcare whose experience with a specific antibiotic has left his body slowly deteriorating over time. The pharmaceutical company promoting the drug is one of the East’s primary targets, or as they would explain it, attacking this company is one of their “jams.” Who wouldn’t want to get back at these people?

Plots like these are what make it genuinely difficult to be against the East, while it’s also not easy to support them completely. Batmanglij makes us ask ourselves what is truly fair. What is justice, and is it ever an eye for an eye? Sarah’s open mind yet open questioning of the group’s actions also reminds us that there are often many solutions to a single problem.

The East may not make you pick up an environmental cause, but it probably will make you think about whom, if anyone, is out there to help the defenseless. There’s certainly a line between activism and terrorism, but it can be absurdly discreet, as captivatingly proven in this film.

Grab what you think is your definition of justice, and then head to a Sundance screening of The East.