Two hundred years in the future, in a fully colonized solar system, police detective Josephus Miller is given the assignment to find a missing young woman, Julie Mao. Joining his task is James Holden, former first officer of an ice freighter who is involved in an incident caused by the tense relationship between Earth, Mars and the Belt. Far from their struggles in space, United Nations executive Chrisjen Avasarala works to prevent war between Earth and Mars. Soon the three find out that the missing woman is connected to a vast conspiracy that threatens all humanity.
The Rocinante crew deals with the fallout over Naomi's betrayal while caught in the middle of the war between Earth and Mars. Avasarala and Bobbie hatch an escape plan.
The Rocinante answers an unexpected distress signal. Bobbie and Avasarala find themselves being hunted by a mysterious captor. UN Secretary-General Sorrento-Gillis brings in a colleague from his past to lend an ear during this crucial time of war.
Earth strategizes a costly ploy to gain advantage in the war against Mars. Anna struggles to convince Sorrento-Gillis to do the right thing. Avasarala and Bobbie seek refuge aboard the Rocinante.
The Rocinante tends to wounded Martian soldiers in exchange for supplies; Avasarala struggles with how to disseminate a key piece of evidence despite being in hiding.
The search for Prax's daughter comes to a head; Admiral Souther's men plan for mutiny aboard the Agatha King.
The final battle between Earth and Mars threatens the very future of humanity. A new monster is unleashed on Prospero Station. Anna receives the smoking gun she needs.
All eyes turn to the edge of the solar system as a mysterious new presence emerges. Naomi recommits to her roots. Drummer butts heads with a seasoned new commander aboard the Behemoth. A young Belter makes a name for himself.
An old friend taunts Holden with the answers he seeks. Naomi struggles to fit in. A mysterious low-level tech aboard the Thomas Prince enacts a terrifying plan.
The Rocinante seeks a new game plan as they attempt to avoid capture. Melba's true motives are revealed. Naomi is torn between identity and ideal. Anna seeks a way to stay aboard the Thomas Prince.
Holden sees past, present, and future. A ghost from Melba's past threatens her mission. Bobbie struggles to trust an old friend as she leads a group into uncharted territory.
Drummer and Ashford find themselves trapped with few options for survival. Anna tends to the wounded masses as Melba continues to hunt down her prey. The Rocinante crew struggles to survive as Naomi reunites with her true family.
As survivors arrive to the Behemoth, two factions form over how to handle a life-or-death threat. Holden grapples with what he's seen and the choices he must make.