Principle now broadcast on HBO Max, as well as on Amazon, Apple TV and Google Play. Unlike cinemas, you can now turn on subtitles and rewind confusing material to figure out what’s going on.

Christopher Nolan’s sci-fi spy has been criticized for its confusing plot and even his its mixing made dialogue inaudible. And yet the jaw-dropping action sequences, James Bond’s stylish wardrobe, and heart-wrenching soundtrack still manage to engulf you in an intoxicating wave of blockbuster show.

But what about this time-consuming plot? Here are some answers to what happened.

Read more: The Haunting of Bly Manor ending explained & all your questions answered

Warning: Spoilers ahead

What is inversion?

In the future, technology has been developed that reverses the entropy of people and objects to move back in time. Entropy is a complicated physical concept that explains why some processes occur spontaneously while their temporal inversions do not. “Melting ice, dissolving salt or sugar, making popcorn, and boiling water for tea are processes that increase entropy in your kitchen,” according to an explanation. In Tenet’s universe, the protagonist (John David Washington) is represented by an inverted entropy bullet that returns to his weapon. You can tell if a human has been inverted, because they have to breathe special oxygen through a mask – ordinary air does not pass through inverted lungs. If you contact your “advanced” self, it causes “self-annihilation”, which means you are killing yourself. Complicated stuff.

What is the algorithm?

Nine objects, hidden in nuclear faculties, form an algorithm that reverses the entropy of the Earth. Triggering the algorithm ends the world.

What is Sator’s plan?

Russian oligarch Andrei Sator (Kenneth Branagh) is in contact with an unknown agency in the future. Sator plans to trigger an apocalyptic device, also known as the algorithm, that will reverse the entropy of the entire planet. He dies of inoperable pancreatic cancer and thinks that if he can’t live, no one can. Sator returns to vacation with Kat (Elizabeth Debicki) in Vietnam when they were both happiest, planning to die there peacefully and trigger the doomsday device with a dead man’s switch tied to his heartbeat.

Why does the future work with Sator?

In the future, everything is destroyed. An unknown agency is working with Sator to kill everyone in the past because they are responsible. People of the future believe that reversing the entropy of the Earth will prevent climate change. Having no other choice for their survival, they are ready to destroy their ancestors and threaten their own existence – the grandfather’s paradox.

Why Sator?

Sator grew up in the Soviet Union in a small community acting as a “closed” or “secret” town with sensitive facilities, such as nuclear research sites with a plutonium production plant. As a teenager, Sator was in the right place at the right time when he unearthed a piece of the algorithm in the rubble of his home in Siberia. The scientist from the future who created the algorithm hid the coins in time, realizing that no one should have the technology. The unknown agency tasks Sator with collecting the coins and depositing the finished algorithm in the “dead drop” of his nuclear hometown, where they will find it centuries from now. The agency buries gold bars in reverse time which Sator digs up for payment.

Who saved the protagonist at the opera?

While foiling the terrorist siege of the Kiev Opera House, the CIA secures an unidentified object (which later turns out to be a piece of the algorithm). After recovering the object, the protagonist, a CIA agent, is saved by a masked gunman. We see the shooter carrying a red string on his back – the same red string Neil (Robert Pattinson) wears on his backpack at the end of the movie. So it was Neil who saved the protagonist during the opening shootout.

How does the “temporal pincer movement” work?

Let’s look at this through the scene where the protagonist steals the “plutonium” from an armored car for Sator. Half of Sator’s men enter through a portal called a “turnstile”, allowing them to step back in time, while the other half advance. Sator leaves with the piece of the Algorithm for the benefit of the knowledge shared between the two teams. It is the “movement of the temporal pincer”.

How did Kat survive after being shot?

Sator shoots Kat with an inverted bullet, which means radiation poisoning as well as regular bullet damage. To avoid this, the protagonist and Neil take her through the time turnstile so that she also goes back in time, just like the bullet. They then take her to Oslo’s “freeport” art storage facility and pass through another turnstile to step back in time.

Why is Kat under Sator’s control?

In short, Kat knowingly sold Sator a fake painting. To gain his trust, the protagonist and Neil attempt to steal the painting from the “free port” of Oslo airport.

How did they get away 2 explosions in this building?

In the closed city where the algorithm is stored, two teams participate in the operation to stop the detonation of the apocalyptic device. The red team is moving forward in time, while the blue team is in reverse. They use “pincer temporal movement” over a 10-minute period, with the blue team being separated from the red in the helicopters. By setting a timer, the red team (those moving forward in time) detonates a bomb in the lower half of the building at the 5 minute mark, while the blue team does the same in the top of the building in counting down from 10 minutes at the same time.

What happened at the end with Neil?

In the algorithm room, the protagonist and Ives (Aaron Taylor-Johnson) encounter a locked door. On the other side, they see the corpse of a masked soldier, who wears a red cord on his backpack. One of Sator’s men tries to shoot the protagonist, but the masked man comes back to life, takes the bullet and unlocks the door, allowing the protagonist to prevent the end of the world. He then goes out of the tunnel in reverse. We later see the red string on Neil’s backpack, when he reveals that he was recruited by the protagonist in the future. So the masked soldier who dies is Neil.

Who is Neil?

Here’s a fun theory for fans: Neil’s identity can have an extra layer. He has a few similarities to Kat – including Pattinson’s dyed blonde hair and chic English accent – and he shows a level of tenderness while caring for her that suggests a deeper connection. Which has led some viewers to assume that Neil is in fact Kat’s son. We see Kat’s little boy, Max during the movie, who may have grown up as Pattinson, and then was reversed to return and help the protagonist defeat his vicious father. Hey, that’s a theory.

Who is the protagonist?

The protagonist travels to London to rescue Kat from arms dealer Priya (Dimple Kapadia), who thinks she needs to sort things out. The protagonist shoots Priya, realizing that he is going to go back in time and found the secret organization Tenet.