The Expanse follows the case of a missing girl whose disappearance brings together a diverse and disparate group of characters in a race to uncover a conspiracy never seen before in human history. Oh, and it takes place hundreds of years in the future. That all said, this gallery will give you the who's who that you need to know.
First up is Julie Mao. She's the aforementioned missing girl. She's an heiress whose political sympathies lie with the disenfranched residents of the Asteroid Belt.
This is Miller. He's a detective with a private security firm called Star Helix. He lives on Ceres, a colonized asteroid in the Belt. He's assigned to find Julie Mao. What his investigation reveals....well, that's another story.
This is Jim Holden. Holden is a high ranking officer on The Canterbury, a giant spaceship that hauls ice from the moons of Saturn to be used as water in the Belt. He's an upstanding guy, but when he commits to something he COMMITS. That trait will uncover more revelations about the future of humanity than he could ever imagine.
Alex Kamal is one of the pilots of the Canterbury. He's from Mars...but has a Texan accent (long story). Despite a seemingly good ol' boy demeanor, Alex is a solid, dependable professional who can be counted on in a crisis. Of which there will be many.
Chrisjen Avasarala is the Deputy Undersecretary of the United Nations. But her title is probably the least impressive thing about her. Avasarala is a political whiz who sees the inevitiable conflicts due political unrest in the Belt, not to mention the brewing cold war that is the power struggle between Earth and Mars. She's determined to protect Earth's interests at any cost. Emphasis on the any cost.