I love movies like Sicario, where right from the opening scene you know that they mean business. In the opening shot, we see a development at the border town of Chandler, Arizona. As the shot lingers, FBI agents slowly creep into frame. A drug raid is about to go down. Now ordinarily, this is the way any action move should be set up. Open with an explosive action scene that establishes the tough hero and how tough he or she is. It’s a well worn cliche that’s no longer exciting. Sicario is different, though. As soon as it starts, you don’t get the feeling that you’re going through the motions. It doesn’t have the glossy look and feel of a summer blockbuster. Instead, there’s a terrifying feel to it. It’s a tone that makes you feel like you’re in the raid, like you too could be killed at any minute. It’s a nerve-wracking experience, and one director Denis Villeneuve never lets slip through the entire movie.

Our hero is Kate (a never better Emily Blunt), who’s an FBI agent involved with the opening raid. While somewhat successful (dozens of bodies are found at the house), a bomb is set off, killing a few of the agents. Reasonably upset and frustrated by their lack of progress, she agrees to join a team that will go across the border to try to catch the men responsible.

The team is being led by Matt, who’s played by John Brolin. His relaxed, laid-back demeanor is comforting at first. After all, if he isn’t scared about what their going to do, why should we? He shows little concern over their first mission where they have to cross the border, grab a man for questioning, and come back. What do they need this man for? Well, that’s where things begin to get shady. Matt deliberately seems to be keeping Kate in the dark about what’s going on, and his true intentions are increasingly questionable.

Even more questionable is a man named Alejandro (Benicio del Toro) and his purpose. From the start, Matt says he’s part of the team but won’t say why or what his purpose is. Even when Kate asks him, he’s vague and unclear about who he even works for. And after seeing how they handle the incredibly tense border crossing, the idea that they might not be on the FBI’s side doesn’t seem that far fetched.

It’s questions like these that drive Sicario, not just tense action set pieces. Actually, there’s surprisingly few of them. But this movie doesn’t need them. The increasing sense of dread is what infuses the plot. Kate’s slow realization of just how in over her head she is is more exciting than any shootout. The questions that are brought up are more horrific than any crime scene. The reality it presents is a dark one, where even the definition of good guys and bad guys is unclear.

You can argue whether or not Sicario is all that original. So if you really want to nit-pick, I guess you can say that what Sicario has to say has been said before. But why bother? When the results are this well executed and engrossing, who cares. It’s unflinching brutality is hard to look away from. Roger Deakins cinematography is atypically stunning (nighttime shots have rarely looked this good). The droning score by Jóhann Jóhannsson (who composed The Theory of Everything’s amazing music) can induce nightmares all on it’s own. Plus, Emily Blunt is in her top form, and Benicio del Toro has rarely been better. I had forgotten how menacing he can be, which is only heightened by the fact you don’t know which side he’s on.

It all adds up to one of the most riveting movie’s of the year. It’ll fester in your mind for days.