Tenet: First viewing notes

I watched Tent in the UK on Saturday 29th August.

With people are still being cautious as lockdown eases, I imagine most screenings were, like mine, barely full. The film is also yet to be released in the US. A weird result of this is that online discussion of the film is still at a very early stage, and simply Googling for some explanations yields a long list of clickbait articles from mainstream publications that give basic plot summaries and even get certain details wrong!


Edit: Obviously time has passed and people have collectively figured a lot of stuff out! I recommend starting with the FAQ on the Tenet Reddit. Meanwhile, I’ll leave this post up as a kind of time capsule.

One useful resource is this more detailed summary of the film, which serves as a useful recap and explains some details you may have missed.

In the absence of good discussion, I thought I should just lay out what I’ve been able to figure out myself and the questions I still have at this point. It certainly seems like Christopher Nolan is the kind of guy to plan all this stuff out carefully, so there probably is some sense to be made here!

Plot details that were weird on a first viewing

In the initial Opera scene, The Protagonist (John David Washington) is saved by someone firing inverted rounds, who has some sort of distinctive orange tag. This turns out to be Neil (Robert Pattinson). It seems very open quite where or when he came from, or what he was doing. Presumably acting under later-timeline-Protagonists orders, or possibly even trying to acquire The 9th Piece of the Algorithm in the first place? I’m not sure how to figure it out, but it also doesn’t really matter.

There’s a whole bit about what the protagonist was really trying to do and why did it go wrong, made harder to understand by the (apparently deliberate) muffled mixing of the dialogue. It seems like they are working in concert with some Ukrainian special forces to extract a compromised double-agent and what they believe to be some plutonium. However, some of the Ukrainian forces have gone ‘rogue’; this is why we see one of them helping the terrorists, and why we some of them kidnap the protagonist and torture him. Presumably this was also part of Sator’s gambit to obtain this 9th piece of the algorithm, but I’m not quite clear on that.

When the protagonist meets Neil, it’s a bit odd – he knows he drinks diet coke! He brushes it off but we know something is up. It turns out Neil has been interacting with a future-version of the protagonist all along. It’s not clear if Neil has travelled back a long way for this mission, or if later on the protagonist gravels back a long way to recruit Neil, but I guess it doesn’t matter. It’s a bit more odd that presumably Neil is briefed on how to interact: “Don’t tell me anything about Tenet or who you really are, but feel free to drop weird hints that might make me distrust you initially”.

The car chase has something odd going on, and it turns out this is because a key part of it isn’t shown to us when we go through it ‘forwards’. What we missed was the protagonist taking the 9th Piece out of the case, then seeing himself in the silver car – and presumably out of intuition, he throws the piece into that car.

Not understanding what has happened, when the protagonist goes on to invert, he gets into the silver car, not realising that the 9th Piece is in it. he rejoins the car chase, and the piece ‘throws itself’ out the window back into his original self’s hands. Only then does he realise how it all works.

I don’t particularly understand how Sator was then able to figure out where the 9th piece ended up, but given he was doing a temporal pincer movement, it’s easy to imagine he could have figured it out.

The palindromic interrogation scene is kind of deliciously mad – Sator, moving backwards in time, is trying to get information out of the protagonist, who is moving forwards in time. Again, I could barely catch the dialogue, as it’s broadcast over a reversing-radio and the audio is hard to make out. The only way to really make sense of this is I think to carefully read through the script forwards and back, but right now I just assume it makes some kind of sense.

There’s some complicated stuff to do with injuries. While inverted and travelling back to Oslo, the protagonist has pain in his arm, which gradually becomes worse, then a bleeding wound; this all then leads up to the point when he is fighting with himself, and gets stabbed in the arm with a lock pick. So, while travelling backwards, healing goes backwards – okay. How does this then work with how they are able to keep Kat alive after she gets shot? I don’t follow that yet.

Edit 1: A thought experiment: you build a clock and set it to midnight. You wait for 1 hour, then enter an inverter with the clock, and come out going backwards. You wait for one hour (going backwards in time), looking through the glass and seeing yourself manufacturing the clock (it looks like you are dismantling it). What time does the inverted clock show now? Midnight, or 2pm? I’m not actually sure, and you really need to know that to think through the injury logic!

In the final battle, there’s some complicated stuff with Neil. The protagonist needs to get through a gate; on the other side he sees the dead body of someone with a blue arm-band and that orange ‘tag’. That person then gets un-shot… and turns out to be Neil, who understood how this all worked and travelled back there to make sure the door got opened, even though he knew he would die. The only part I don’t understand here is the mechanics of opening the door for the protagonist… if he’s travelling backwards, does that mean he did it by closing the door?!


There are some questions about exactly what does and doesn’t work when you’re inverted. It’s shown that you can’t breathe normal air – they say something like ‘the lung’s valves don’t work’? That seems odd though, what about your heart’s valves? I would presume the action of breathing increases entropy; if you try to do it with non-inverted air, I guess that’s a contradiction in chemistry/entropy, so that’s fair enough. Heart valves are fine because your blood is also inverted!

It’s not shown in the film, but what does this mean for eating, and to recall Red Dwarf’s take on the genre, excreting?! I presume you can only digest inverted food, but probably excreting is fine as everything inside of you is also inverted?! I can understand why they wouldn’t show this, although I did wonder about how they had enough food and air to survive going backwards in time for multiple days. Perhaps they have a small inverting ‘pump’ that can convert air and liquid food?!

Still, this doesn’t seem quite consistent with the injury problem – if you are inverted, the entropy of your body is now going backwards too. That means wounds should heal, not develop. I guess unless they were caused by something going the other direction in time? I definitely need to think that through more carefully…

Finally, one of the interesting ideas in arrow-of-time discussion is that the reason we perceive time as moving in the direction of increasing entropy is purely that creating a memory is an entropy-increasing act. So how are humans able to remember things while inverted? Actually this probably works just fine – whichever way around you are, entropy in your body is increasing in the same direction you are forming memories, so this is fine.

Entropy war

One big problem to resolve with the premise is to figure out what happens when the entropy of objects moving in opposite directions collide. Regular glass has increasing entropy; what happens when it is shot with an inverted bullet? As we see, a hole gets ‘fixed’ as the bullet comes out of it. So if we trace that glass backwards in time, was the hole there all along? Was the glass installed with a  hole in it?!

One part of the film’s exposition does cover it, but I don’t remember it clearly and haven’t found a transliteration of it online yet. The general idea conveyed is that the overall entropy of the world kind of ‘outweighs’ small-scale reverse entropy. You have a paradox in the form of an inverse bullet firing, and intact glass being manufactured and installed; the overall entropy of the world ‘wins’ (they use some analogy like ‘pissing in the wind’ I think). So presumably that means over a period of time, the bullet holes weirdly form themselves, before being undone again.

That’s sort of okay, and you clearly have to deal with this problem somehow; the weirder part is the crashed silver car from the car chase. How did that wreck get there? Did it just… appear? Is the Tenet organisation trying to keep things tidy, and they had to recover the wreck… while travelling backwards in time… so from a forwards perspective some backwards-moving people put the wreck on the road?!

This rabbit hole is actually crucial, because the whole point of the time-war is that the future wants to reverse the entire world, killing everyone alive today. If everything is always consistent, the protagonist points out, then we already know the future fails to do this, because we’re here. But the ‘piss in the wind’ rule (I wish they’d used a different analogy!) means this isn’t so; if the entropy running backwards is ‘strong’ or ‘big’ enough somehow, it would ‘win’ over the current direction of entropy, and we would die. I really want to go over the dialogue from that scene again…

Edit 2: There’s a further question to this.I can imagine the evil future folk formulating their plan. They write a letter for Sator. They watch an inverted version of themselves apparently digging up an old container and pulling the letter out, then walk backwards into an inverter; they themselves walk forwards into the inverter with the letter. They come out going backwards, and from that point of view they put the letter in the container and bury it. The letter is now inverted through time for Sator to discover. But… where is the letter in the time before Sator gets it? Presumably the instructions include the fact that he needs to bury it again to be consistent with the future, that’s fine – but where was it a year before he got it? Couldn’t someone else end up finding it as it continues to move back in time?!

The Master Plan

While I could follow the moment-to-moment action, I was left a bit confused about the bigger picture. How exactly would Sator’s death lead to the end of the world?

Reading up on things, this is now clear. The ‘evil’ future is communicating with Sator, trying to have him recover all 9 pieces of the Algorithm, then bury them somewhere secure, so that they can later dig that up and use it. Sator has a kind of insurance policy. He has a dead-man’s handle; if he is killed, it will broadcast the GPS co-ordinates of the location to ‘posterity’, meaning the future will then know where it is and be able to recover it. So it’s only safe to kill him if you can make sure the algorithm doesn’t end up buried at those co-ordinates – which the protagonist and his Tenet pals are eventually able to do

The other part that is really just skimmed over: why does the evil ‘future’ want to reverse entropy? They imply climate change is the reason. It almost comes across like a kind of petty revenge for climate change, but it would make more sense if the plan is to actually reverse climate change by reversing the entropy of the earth (or the solar system, or the universe?!). However, that doesn’t quite work – if the entropy of the whole world is now going backwards… then that doesn’t mean CO2 is putting itself back into coal-fired power stations that are turning reverse-electricity into coal that they then ‘bury’. If entropy is reversed all over, then everything keeps moving ‘forwards’ in the normal way. Perhaps the future’s plan is more complicated than we are told, or perhaps I’m not remembering it right… either way it doesn’t quite make sense to me yet.

The Final Twist

One cute theory I’ve seen out there is that perhaps Kat’s son Max is actually… Neil! This would explain the slightly weird emphasis on saving this boy’s life (considered in the film roughly on a par with saving the entire world). But I don’t think it quite adds up other than being ‘nice to think about’ sort of idea. In particular Neil’s actions in response to Kat don’t really match up with this idea. I don’t see any strong evidence for this idea.