Season 4 of The Expanse, its first as a global Amazon Original, begins a new chapter for the series with the crew of the Rocinante on a mission from the U.N. to explore new worlds beyond the Ring Gate. Humanity has been given access to thousands of Earth-like planets which has created a land rush and furthered tensions between the opposing nations of Earth, Mars and the Belt. Ilus is the first of these planets, one rich with natural resources but also marked by the ruins of a long dead alien civilization. While Earthers, Martians and Belters maneuver to colonize Ilus and its natural resources, these early explorers don't understand this new world and are unaware of the larger dangers that await them.