Tenet is a movie about the idea that you can reverse the flow of time by reversing the entropy of an object.  This is a fascinating way to look at time travel, although it happens in “Real Time” so you have to live the events in their entirety (forwards of backwards) instead of jumping over them to arrive way in the future (or past) a la Back to the Future.  We break-down how this would work, and what effects it would have on reality, including how an explosion would give you hypothermia and how coming into contact with another version of yourself would cause both of you to annihilate each other.  Hopefully we explain all of this in a way that is less confusing than the movie itself!