Right now, there is no more compelling, no more unnerving, no more mysterious hour of television every week than The Leftovers on HBO.

This past Sunday, the first episode of the third and final season debuted, and it only enforced the notion that Damon Lindelof and Tom Perrotta’s drama is the most consistently engrossing bit of storytelling on any network. The Leftovers has pulled off what only a handful of series have been able to accomplish, it has taken a premise, based on a book (from Perrotta) and from there has evolved into its own thing. Typically these gimmick shows surrounding a single idea can fade as time moves on. The Leftovers has only grown stronger and weirder.

For anyone who is tragically unaware of the story, here is the bare-bones setup: in October one year, two percent of the world’s population disappeared without a trace, without a clue, leaving the rest of the world in a collective state of unbearable anxiety. The first season introduced us to Kevin Garvey (Justing Theroux), a police officer in a small upstate New York town. The second season found Kevin and his family moving to a small Texas town, the only place in the world where nobody departed. From that second season and into the early moments of this third, The Leftovers has spread its wings, tackling a seemingly endless array of storylines and events all connected by a mixture of mystery and fear.

What sets the show apart from others, aside from basically everything in the story itself, is the anxiety it mines from its characters and pushes onto the audience. This is not just a simple hour of TV you can watch while scanning your phone on the couch. It requires attention, it will test your mental resolve, and it will challenge you to identify with the way these people must be feeling in the wake of so much tragedy and despair.

That may not sound like a lot of fun, but believe me it is. Each and every episode teases the viewer with another mystery, clues as to where we may be headed, and it shows us what has happened, allowing the storytelling prowess of its creators to tell us what has happened since we last left our characters. Theroux’s Kevin is the heart and soul of the story and, as we found out in S3E1 this past Sunday (mild spoiler here………….) he may be some sort of new messiah. This will be the catalyst for the entire season, all the while the characters in Kevin’s life endure their own set of trials.

The Leftovers takes an event like the disappearance, and shows how humanity might handle such an unexplained tragedy/phenomenon. Notions of religion pepper each and every scene, and beneath all the tension lies the anxiety of the afterlife. Some believe fully, others have twisted their dogma to fit such a tragedy, and even others – like Kevin – are simply trying to make sense of the day they’re in.

There is no more energizing series on television this spring. On one hand, it’s too bad The Leftovers is closing up shop after this third season. On the other hand, it may be ending at just the right time.