Now that Christopher Nolan’s Tenet is out for home viewing there will be a lot more people who have seen it, and potentially a lot more people who have struggled to follow it.
It does make more sense with subsequent viewings but since it is a two and a half hour movie others may not have the time for this.
Here then is the plot of Tenet laid out in straight forward terms. Spoilers follow.
In a nutshell, Tenet is about a man who is recruited to be part of a secret organisation that is trying to stop people in the future destroying the world in their past/our present. They are doing this not through time travel but with the ability to make certain objects and people travel backwards in time. It seems that to get to a point in the past takes the same amount of ‘time’ to get to a point in the future only in reverse. There is an Anglo/Russian arms dealer who is terminally ill and has agreed to help those in the future end all of life and existence because if he can’t have it then no one should. He has a bomb that is connected to his heart rate and once his heart stops then the bomb will detonate. If he can find all the pieces of an algorithm, rendered in hard copy, that controls the time reversal, or ‘inversion’, and place it next to the bomb when it goes off then it is game over. Technically this is happening in the past but time is on a loop that weaves around itself so it won’t take place until the events of the future, or the current time, have occurred to allow it.
There is lots of action where time is running forwards and backwards in perfect parallel, so for example you can see yourself entering the time altering machine as you enter it, but it all cumulates in an old Russian town where two troops of soldiers create a temporal pincer movement to get to the bomb. One team is going backwards so can debrief the team that is going forwards before the mission starts even though they seem to be operating simultaneously. This almost ensures success but in the end one of the agents has to go back again to save the hero from getting shot once the job is complete subsequently sacrificing his own life in his immediate future but their immediate past. The scheme is also nearly derailed by the arms dealers wife who has gone back to the key point in time to stop the man killing himself before they have been able to take the algorithm away from the bomb but she wants him to know that he has failed in his plan so she pulls a gun on him and kills him a little too soon. Fortunately it all comes together in time, as it were.
There is a lot more in the plot about the arms dealer having hold over his wife due to a forged Goya that could implicate her in fraud and a side mission to steal this from a secure airport warehouse, as well as there being another arms dealer in India who is one of the good guys but wants to kill everyone involved in the mission so that it all stays secret. In the end it turns out the guy who is recruited at the start is actually the man behind the whole thing at the end but he doesn’t know this yet as it is in his future.