As Green Room opens, we see a van in the middle of a corn field, everyone in it sound asleep. The camera pulls back, and we see the path the van followed as it swerved off the highway and into the field. A sleepy driver drove off the road; funny, though also scary. And a metaphor for the entire film, which is about a group of musicians that has veered off the road, and is trying to survive.

In the van, The Ain’t Rights, a punk band, traveling from gig to gig, siphoning gas to keep going, playing wherever they can. They’ve essentially decided to call it quits, at least short-term, but accept one more engagement, because it pays enough to get them home.

So they show up, to a log cabin-ish venue in the woods, a bar where most of the patrons are skinheads, on the walls neo-Nazi regalia for decorations. And so their lead singer, Pat (Anton Yelchin), picks what I think was a Dead Kennedys anti-skinhead song, ‘Nazi Punks F off’ to begin their set. Very punk rock; edgy and tense and real. The crowd reacts furiously, throwing things and spitting at the stage, but we don’t sense The Ain’t Rights are in actual trouble. Yet. But that will come.

When they finish their set, they’re escorted by security up some stairs to a green room. And on the floor, they can see a woman with a knife sticking out of her head. Dead.

Panicked, they pull out a cell phone and call 9-1-1, reporting ‘a stabbing’ and the address just before the phone is confiscated by security. The rest of the movie is about this punk band, fighting for survival, attacked by neo-Nazi skinheads working for the venue’s owner, Darcy, played by none other than Patrick Stewart.

Darcy’s basically trying to clean up a mess. The venue’s headline band’s lead singer, high on drugs, killed the girl, his ex-girlfriend, because she was planning to leave him, and the whole skin-head lifestyle, behind. (That mystery, about who killed the girl, isn’t particularly important, and gets resolved very quickly. This movie isn’t about who-dun-it, it’s more about who is likely to survive).

The result is a fascinating film, a horror thriller that manages to transcend the essential conventionality of its structure. The writer/director, Jeremy Saulnier, clearly knows his subject matter. The day to day interactions of the band is completely convincing. I don’t know Saulnier’s background, but the film felt like it was written by someone who toured once with a band, who then based a screenplay on the jokes they shared about some of the sketchier venues they played. ‘What if we went into the green room and there was a dead body on the floor?’ That kind of thing. And then Saulnier took it from there.

I don’t know much about the whole punk rock/skinhead death metal scene. I sense that it contains an almost infinite numbers of sub-genres, and that Saulnier knows intimately the differences between them. The details of the world of this film is so convincingly rendered, I was completely with it throughout, despite my own ignorance of the film’s background. It felt very Zola-esque, a perfectly realized simulacrum of the denizens of a demi-monde. I loved Alia Shawcat as Sam, their guitarist, her shoulders hunched over her instrument as she plays. I loved the way they started songs, with Yelchin suddenly shouting, very quickly, “2, 3, 4” and instantly a hard-driving punk beat starts up. I loved the camaraderie of the band, how quickly spats get resolved and decisions made.

Although it’s not remotely a political film–its a horror thriller, with punk rock/skinhead setting–I can’t help but see a tremendous political subtext. It’s a film, after all, about neo-Nazis terrorizing punk rockers. About skinhead death metal vs. punk–immensely political music worlds colliding lethally. All under the deceptively benevolent direction of Patrick Stewart.

Because Darcy, the film’s uber-villain, is also genial and sympathetic. We instinctively feel that we can trust him; that when he tells the band members that he wishes them no ill, that he means it. Of course, he’s lying. Of course, he’s using a gentle manner to mask an essential sociopathy. So what is that characterization intended to convey about skinheads generally?

Darcy gives orders, intending them to be obeyed, and at times his followers do just as they’re told. For example, knowing that a 9-1-1 calls has reported ‘a stabbing,’ he orders one of his followers to stab his brother. The cops show up, are given a stabbing victim and perp, and drive off, satisfied. Leaving Darcy to complete his clean-up. Including, of course, disposing of witnesses.

Those extra resonances, the film’s implicit politics and the intersection of politics and music in the genres it explores, are what moved this film from exciting and powerful to unforgettable. I don’t know what it all means, but I want to learn, and spent the morning listening to The Misfits and Fugazi, trying to understand. Green Room got under my skin, is what I’m saying, and I’m grateful. It’s very seriously R-rated, and some will find it an unpleasant viewing experience. But I loved it.