First, I believe a little (spoiler-free) information might be helpful prior to watching the show, because the viewer is thrown right into an incredibly detailed world where much is shown rather than explained (which is certainly an elegant choice in terms of storytelling and world-building, but there's so much going on and every shot is packed with so much visual information that it can be a little confusing during the first 2 or 3 episodes). So what you need to know is this: A couple of hundred years into the future, humanity is spread out throughout the solar system and divided into 3 opposing forces who are on the brink of an all out war for political power and resources (mainly water - which is harvested in the form of asteroid ice). The 3 fractions consist of the two superpowers Earth (governed by the U.N.) and Mars; the third party are the "belters", which is basically everyone unfortunate enough to be living on poor dwarf planets like Ceres or other large rocks in the asteroid belt (hence the name "belters").
Those belters are the future equivalent of the 3rd World population, as they represent the poor, exploited and underdeveloped colonies in the solar system. Many belters feel represented by the "Outer Planets Alliance" (short: O.P.A.) which is a radical group demanding more autonomy and fairer distribution of resources for the inhabitants of the asteroid belt, but is viewed as a terrorist group by Earth and Mars. Belters are badly affected by the harsh conditions in low (or even zero) gravity (which is often referred to as "low-G" or "zero-G"), as well as low oxygen levels and the strict rationing of water; their bodies develop less muscles and their bone structure has less density compared to that of humans born and raised on Earth or Mars. The belters' life expectancy is roughly half of that of humans living on Earth.
So that's the backdrop to the story told in 'The Expanse', and it all may seem a little complicated at the start, because the plot unfolds through several separate story lines. The key parts of the story are told through the eyes of three different protagonists: a high ranking U.N. official on Earth named Avasarala (played by Shohreh Aghdashloo); a cynical belter police detective named Miller (Thomas Jane) whose story starts on Ceres; and a young executive officer named Holden (Steven Strait) working on an ice freighter in space. Although those three don't know it (yet), their stories are connected - and that's all I'm gonna say about the plot, because this show deserves to be watched unspoiled.
Featuring visual and narrative elements that reminded me of almost every sci-fi film I ever loved - 'Alien', 'Outland', 'Serenity', 'Blade Runner' and many more - this is an R-rated space opera no sci-fi fan should miss. And although it probably can't compete with 175 million costing blockbusters like the new 'Star Trek' movies in terms of visual effects, 'The Expanse' looks fantastic. Given the insane amount of effects work involved, it must have been a very expensive affair for SyFy (who ordered the series from production companies Alcon Television and The Sean Daniel Company), and although I doubt they were able to afford the kind of budget HBO usually spends on shows like 'Game of Thrones' or 'Westworld', in terms of scope and complexity, this new SyFy show easily matches HBO's flagships (it appears Syfy is trying to get rid of its reputation as "shlock-channel").
The storytelling is meticulous and perfectly paced; the world-building richly detailed and always credible, and the patient viewer who doesn't demand everything be explained within the first episodes is rewarded with a thrilling, mysterious tale of adventure and discovery. The cast is terrific (especially Thomas Jane who seems to fit his character like a glove) and the writing manages the astounding feat to elegantly lead us through a very complex world and complicated story without ever feeling forced or weighed down by expository dialogue. Showrunners/writers Mark Fergus and Hawk Ostby (known for their Oscar nominated work on the screenplay for 'Children of Men') really have done a fine job bringing the series of novels by James S. A. Corey (aka Daniel Abraham and Ty Franck) to life. Highly recommended to every sci- fi fan: 9 stars out of 10.
Favorite TV-Shows reviewed: http://www.imdb.com/list/ls075552387/
Favorite films: http://www.IMDb.com/list/mkjOKvqlSBs/
Lesser-Known Masterpieces: http://www.imdb.com/list/ls070242495/
Favorite Low-Budget and B-Movies: http://www.imdb.com/list/ls054808375/