Whoa! Tenet is an intense and challenging movie. This another of Christopher Nolen's time movies: Momento (2002), Inception (2010), and Intersellar (2014). The story involves timelines running forward and backward, simultaneously. I have to admit, it's hard to follow. It helps to watch it twice, the first time to get the basics of what's happening, and a second time to more fully understand what's really going on.