The Expanse takes place hundreds of years in the future where mankind has colonized the solar system. Thanks to the ingenious engine drive invented by Solomon Epstein, a man living on Mars, we've established settlements on the Moon, Mars, the asteroid belt, and Jupiter. Yet, as far as we've progressed, the stars are still out of our reach.
For humans it's business as usual: the endless struggle for scarce resources continues. Tribalism. Rasicm. Bloodshed. Earth and Mars, now the two superpowers, face off in a cold war, while the underclass of Belters (those born on the asteroid belt) grow increasingly tired of being exploited by the inner planets. An all out war threatens to erupt at any moment - Earth vs Mars vs The Belters.