Understanding the movie--TENET in a thread.

PSA: This is a spoiler if you haven't seen TENET.

Before we begin, there are things that don’t get explained until later in the film but are worth covering up top.

Things like this whole movie takes place in a world where the future has declared war on the present because it’s upset about climate change. To do so, it uses a technology called “inversion,” by which objects and people can travel backward in the flow of time.

So the protagonist is a CIA agent looking for a MacGuffin during a false-flag terror attack at the Kiev Opera. In the chaos, his life is saved by a mysterious figure in black, who kills a henchman with a bullet that travels backward. But the protagonist's cover is blown...

... So he’s captured by the bad guys. He takes a suicide pill to avoid giving up his secrets.

Except the suicide pill is actually a test! The protagonist wakes up on a boat, where his boss explains that his new mission is to join something called Tenet.

The protagonist then goes on to meet with a lab scientist, Laura who is tasked with delivering some equally magical exposition. The bullet Washington encountered at the opera is just one of many “inverted” objects that scientists have discovered traveling backward through time.

People going forward in time can interact with them, but it’s weird: To pick an inverted object up, you have to imagine yourself dropping it.

“Don’t think it, feel it,” Laura says.

This is the movie’s mission statement.

The protagonist traces the inverted bullets to an arms dealer--Sanjay in Mumbai. To get a meeting, he needs a sidekick. Where Neil comes in.

they bungee jump into the arms dealer’s building, where they learn three surprising facts.....

One, the dealer is a woman, Priya! Two, she knows about Tenet. And three, she sold the bullets to the villain, Andre sator, who is acting as the future’s representative in its war on the present.

Also that sator communicates with the future by leaving messages for “posterity.”

Priya then links the protagonist to an MI6 agent, Mr Crosby who explains that the way to get to Sator is through his wife, Kat, who is being blackmailed by sator over a fake painting she sold him...

The protagonist then links up with sator's wife, Kat in a bid to get to Sator.

As part of a quid pro quo with Kat, The protagonist and Neil decide to steal the forged painting located in a free port (a real thing where rich people can secure their valuables without paying taxes on them) at the Oslo airport.

They pose as fancy men while their friend--Mahir crashes a cargo plane into the airport.

But before they can get the painting, two masked guys — one moving forward, one moving backward — appear from a mysterious portal in Sator's vault.

Who are these guys? We will get to that.

Anyway, the protagonist is about to kill his guy, until Neil stops him. The mysterious masked men get away, and there’s no painting in the vault. How did sator know they were coming?

It’s all very confusing, but luckily they go back to Mumbai and Priya explains it to them.

The device in the vault was an invention from the future called a Turnstile, which allows people to invert themselves and travel backward in time. Thus, the two people in the vault were actually one person, flowing backward and forward out of the moment that he entered the device

Also, Sator was the one behind the terror attack at the opera, and he’s still on the hunt for the MacGuffin.

The protagonist then gets in good with Sator, first by dropping a reference to the opera, then by saving his life after Kat threw him off a catamaran, and finally...

... by offering to help him steal the MacGuffin, which is apparently plutonium.

Sator also told his story: He grew up at an abandoned Soviet nuclear facility, where he discovered a cache of gold and a message from the future. (The protagonist witnesses him receive a shipment of inverted gold bars, which is how the future has been paying him to do evil.

The protagonist and Neil then successfully pull off a highway heist in Tallinn, only to discover that the MacGuffin is not plutonium at all but something timey-wimey. Sator and his henchmen show up and there’s a car chase.

They’re all wearing oxygen masks and traveling backward through time! Inverted Sator threatens to shoot Kat except the protagonist gives him the case containing the MacGuffin, which he does.

At the same time, an inverted silver car uncrashes and joins the chase.

Inverted Sator tries to kill Kat in a car crash, but the protagonist saves her. They’re both captured by Sator's henchmen. Neil then says he’s going to call in “the cavalry.”

The protagonist wakes up in a warehouse next to another Turnstile, where Inverted Sator uses..

... a walkie-talkie to translate his backward speech into regular English

He says the MacGuffin wasn’t in the case and asks the protagonist where it is. The protagonist refuses to tell him, and so Inverted Sator reverse-shoots Kat with an inverted bullet.

The protagonist lies and says he hid the MacGuffin in the glove compartment of his car. Just then, a forward-time version of Sator enters the room, but before he can do more evil stuff, he’s chased into the Turnstile by a squadron of troops led by Ives.

Inverted Sator then walks backward into the Turnstile too. (When you enter a Turnstile going forward, it looks like two people get sucked into it; when you enter one going backward, it looks like two people are coming out of it.)

Ives reveals to the protagonist that he and his troops are “posterity” — soldiers from the future working for the Tenet organization.

The protagonist wonders how Sator seems to know everything that’s going to happen, and he accuses Neil of being a mole.

Ives then explains that, nope, the sator is actually sending half his men forward in time and half backward, executing a “temporal pincer movement.”

So the protagonist decides to follow sator through the Turnstile; that way, he can get the MacGuffin and Kat won’t die, because...

her body will be inverted, thus making it just a normal bullet wound to the stomach.

The troops give him a crash course in Inversion 101: You’ve got to wear an oxygen mask because your reversed lungs can’t breathe normal air, and whatever you do, don’t physically touch your past

The troops gave him a crash course in Inversion 101: You’ve got to wear an oxygen mask because your reversed lungs can’t breathe normal air, and whatever you do, don’t physically touch your past self. Also, every heat transfer works the opposite of the way it normally would.

So the protagonist steps through the Turnstile and starts going backward in time. He steps into a car outside the warehouse … which is the same silver car that was in the chase earlier!

He replays the previous car chase in reverse, but this time we see something we didn’t in the first go-round: the MacGuffin leaping out of the silver car and into forward-protagonist's hands — which means that, in forward-time, he threw it to his inverted self in the silver car

The silver car then crashes, in the same crash we saw happen in reverse earlier, and while Inverted protagonist was trying to escape, Inverted Sator drops a lighter and sets the car ablaze.

Except because the protagonist is inverted, the heat transfer actually works in reverse

instead of being burned, he only gets hypothermia! He wakes up in an air-locked container, where Neil, Kat and some of the troops are all traveling in reverse a week back in time to the Oslo airport so they’ll be able to use the Turnstile there to get themselves going forward

The only time they can sneak into Sator's vault is the time they crashed the plane into the airport, which means that once The Protagonist gets into the vault, he comes face-to-face with his past self, and we get the same fight we saw before, only in reverse.

Luckily, since future protagonist is wearing a full-on gimp suit, there’s no physical touching. (We also get a clearer view of why it looked as if reverse protagonist was shooting his gun at forward protagonist....

He was actually trying to empty the clip so his past self couldn’t use it against him. The protagonist gets into the Turnstile, after which he fights the past neil who figures out that he’s the future protagonist but keeps the secret from past protagonist.

So later Inverted Neil and Inverted Kat go back through the Turnstile too, so now they're all moving forward again. We’re on to the grand finale.