Tenet is a science fiction action movie set in the present. An unnamed CIA agent (John David Washington), our Protagonist, is recruited by Tenet, a secretive organization waging a time war against the future. Apparently in the future people develop technology to reverse an object's (or a person's) chronological flow it starts moving backwards through time. Not only can it be used to send objects and information from the future to the present but it allows agents to do ops through history, by working backwards from the end.

The Protagonist is partnered with Neil (Robert Pattinson) and they're tasked with stopping arms dealer Andrea Sator (Kenneth Branagh) from assembling the seven pieces of an artifact that will destroy the world (there is some philosophy about why people in the future would want to destroy the past and why Sator is helping them, but to be frank maybe a bit confusing).

This leads to the typical big-budget action movie sequences except now you have people and objects moving backwards in time to contend with (and as we find out later even Protagonist and Neil going back in time and revisiting the action scenes in a new light). It's both amazingly cool and terribly confusing unless you're paying attention. Meanwhile on a human element the Protagonist falls for Sator's wife Katherine (Elizabeth Debicki) who hates and fears Sator. To stop Sator they need Katherine's help but it may also require sacrificing her...

Tenet is a pretty great movie that uses time travel in a tactical way throughout the movie. There are time travel movies. There are movies that use time travel tactically. But I don't think I've heard of a movie that uses time travel this extensively and especially with things moving backwards in time while the rest of the world is moving forwards.

But even without the extensive time travel I think Tenet would be a perfectly fine action movie. Definitely worth seeing but pay attention please.