I watched the 2004 movie Primer with barely any knowledge of it, which may be the best way to watch it. Shane Carruth wrote, directed, and stared in this detailed sci-fi story about four entrepreneurs who hope to make some kind of breakthrough on one of their garage-lab projects. When Abe discovers that a box they made does something unexpected, he tells Aaron and the two decide to pursue it. The scene below gives you a taste of the movie’s style while showing Abe and Aaron conducting their first experiment.

That’s the pace of the first quarter–realistic talk from scientific engineers who aren’t spelling anything out for the viewers at home. In this scene, I’m not sure Abe knows what’s going on yet, but he works it out and then tells Aaron everything. They’ve invented a time machine.

Since Abe draws this conclusion first, he experiments with the necessary components to make the box work, to make the box larger, and to survive within it–all before introducing it to Aaron.

That’s when the story goes from a bit tedious to mind-bending. Carruth hasn’t given us a simple lark about time-traveling engineers trying to better their lives or two ordinary guys trying to change the course of history. He’s written a story that pushes into the paradoxes bound to occur when someone breaks time’s linear progression.

For example, if someone could go back in time a day or a week in order to prevent a major crime or gain a windfall in the lottery or stock market, once he goes back to do this he removes his motive for going back. If on Saturday he decides to return to Monday in order to stop a crime and he succeeds, what happens when he returns to Saturday again? Having stopped the crime, he doesn’t have any reason to go back to Monday. So what happens? Are the first days overwritten by the second? What if he had discovered time travel during that week; would revisiting the week delay or prevent the discovery that enabled him to go back in the first place?

What if you began to see it the opposite way, as a way to avoid consequences? What if you could go back in time, punch a jerk who deserves it, and return to the same morning as if (no, because) none of it ever happened? What if you could press a reset button to undo everything you’ve done over the last several days?

Primer is a story about all of that, and while it’s easy to understand the danger presented at the movie’s conclusion, it’s difficult to follow everything occurring up to that point. What happens at the birthday party? Who is the guy following them? Where does the man who looks severely beaten come in? The story pushes into these paradoxes without full explanation, giving rise to explanatory videos like this one as well as webpages dedicated to spelling it all out.

Abe: “I’m not into the whole ‘destiny, there’s-only-one-right-way’ thing.”

Aaron: “Abe, I’m not either, but what’s worse? You know, thinking you’re being paranoid or knowing you should be?”

I enjoyed it overall, but it is dense. One reviewer said that though it’s a short movie, it feels longer due to the many details packed into every minute.