WARNING: The following contains spoilers for Tenet, now playing in theaters.

While Christopher Nolan films might defy conventional understanding, they still have to obey some tenets of Hollywood screenwriting, meaning they need an antagonist. For Tenet, the villain is Andrei Sator, a Russian arms dealer and representative for the future. He acts as a go-between for the "descendants," a group from the future that's trying to wipe out the past.

To understand Sator and the descendants, one needs to first understand Tenet's unique method of time travel: inversion. When a material or person is inverted, its relationship to the flow of time is changed. Instead of moving from the past to the future, it moves from the future to the past. By inverting, traveling back a period of time (either days or months or years), and then undoing the inversion process, a person can travel back and forth throughout the timeline freely. But time travel is conducted at a 1:1 speed, meaning you can't jump a hundred years into the past because doing so would first require you to live a hundred years.

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Andrei Sator, the villain of Christopher Nolan's Tenet

Because of this inability to directly affect events occurring in the distant past, the descendants from the future need a person to act as their proxy. In this case, that person is Andrei Sator, with the particular object the descendants are going after being "The Algorithm." The Algorithm is a formula with the ability to invert the flow of time itself. While inverting a person gives one access to an incredible suite of possibilities, it's limited by the fact that the flow of time is moving forward. Truly altering the events of the past without inverting the time stream is impossible; one of the motifs of the film is "what's past is past." If the time stream was inverted, those inverted individuals moving back from the future would be traveling in the "right direction" and might be able to change the events of the past.

Unfortunately for the descendants, the creator of The Algorithm split it into nine separate parts and then scattered them throughout the past, hiding them in nuclear weapon sites. Sator was an inhabitant of a Soviet "closed city," and it was his hometown in particular where a devastating nuclear accident occurred. He was tasked with recovering some of the plutonium released by the incident, and it was here where the future first made contact with him. Because of Sator's proximity to the fall of the Soviet Union, he was around during the point in history where multiple nuclear weapons sites were at their least secure.

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Andrei Sator, the villain of Christopher Nolan's Tenet

It's also possible exposure to such high amounts of radioactivity is what caused Sator to develop terminal pancreatic cancer. This cancer is part of why he's willing to work with the future, as using the algorithm could cause the past to be destroyed or irrevocably altered. At one point in the film, Sator's wife, Kat, asks why he continues to abuse her instead of simply divorcing her. He answers that if he can't have her, no one can. She uses his answer to explain to the operatives of Tenet why Sator works with the descendants, stating that he believes if he can't live in the past, no one can.

While Sator's motives are clear, the reason why the descendants are willing to destroy the past isn't answered until about two-thirds of the way through the film when Sator delivers a poetically phrased line: "their oceans rose and their rivers ran dry." While made obliquely, the quote is a clear reference to climate change. The world the descendants live in is so dramatically altered by the actions of their fossil fuel-using predecessors that they would risk being erased from the timeline altogether, just for the chance to live in a better world. And even if they do wipe out the past, they might just agree with Sator's sentiment about no one deserving to live.

Written and directed by Christopher Nolan, Tenet stars John David Washington, Robert Pattinson, Elizabeth Debicki, Kenneth Branagh, Dimple Kapadia, Martin Donovan, Aaron Taylor-Johnson, Himesh Patel, Clémence Poésy, Denzil Smith and Michael Caine. The film opens is now playing in theaters overseas and arrives in select U.S. cities Sept. 3. Early access screenings will be held at IMAX theaters starting Aug. 31.

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