I will admit upfront that I am biased in this review - one of my favorite films of all time, as a child and an adult, is the original Dark Crystal. It is a wonderful, layered story that speaks to many fundamental elements of what it is to be human, broken down into archetypes of good and evil that are not simplistic, but rather representative of the different parts of us.
This show as a prequel both continues and adds more layers to the story, giving us the history but also showing us what the world prior to the film looked like. Most importantly it shows a world in which basically good and decent people choose to be controlled and exploited by a caste of creatures that see them as existing only to be used as slaves and food.
If the film was an archetypal heroes journey, this show is an allegory of our modern world and everything that is wrong with it. What makes this a masterpiece is that it doesn't preach or talk down to the audience, it captivates with an amazing story that makes you care about all the characters, thus making the realisation about what it is trying to tell you all the more hard hitting.