Holden and Fred deal with infiltrators on Tycho. Drummer's past comes back to haunt her. Amos returns to Baltimore. Alex and Bobbie's investigation on Mars leads to rogue soldiers.

Naomi comes face to face with Filip. Holden and Fred turn the tables. Avasarala closes in on Marco's plot.

Amos and Clarissa are trapped in a collapsed building. Naomi contends with her old family. Holden assembles a new crew on the Roci. Alex and Bobbie make a dangerous discovery in the Belt.

Holden and the Roci go on the hunt. Amos and Clarissa seek shelter on a devastated Earth. Bobbie and Alex fight a desperate battle. Marco makes Drummer an offer she can't refuse. Avasarala returns to a position of power.

Amos returns to Baltimore with Clarissa. On Luna, Avasarala's alliances begin to shift. Alone and adrift, Naomi becomes a deadly lure.

Amos, Clarissa, and a gang of thieves work together to leave Earth. Avasarala tries to head off a brutal military strike. Drummer's new family bonds are tested as Naomi's life hangs in the balance.

Holden and the Roci face off against Marco's forces and Drummer, while Alex and Bobbie attempt a dangerous rescue of Naomi, and the balance of power in the Solar System shifts.

The Rocinante crew make a startling discovery on an asteroid. Avasarala and Bobbie contend with the devastation on Earth. Drummer and her family must make a heartbreaking decision. On Ceres, Marco and Filip's struggles turn inward.

With an unexpected passenger aboard the Rocinante, Holden and crew undertake a dangerous mission that could shift the balance of power in the war. Drummer decides to make an uneasy alliance. Filip wrestles with his guilt.

Avasarala, with the Combined Fleet of Earth and Mars, takes the war to Marco. Filip and Marco's relationship is tested. The war becomes more perilous and personal for Holden and Naomi when the Rocinante is suddenly forced into a battle.

Holden finds himself at odds with his crew when a controversial decision is uncovered. On Ceres, Avasarala struggles to contain an escalating humanitarian crisis. Drummer's growing faction stage a daring raid with dire stakes. Filip, demoted to repair skiff duty, makes an unexpected discovery.

Paths converge on Ceres when Drummer and her fleet arrive to aid the relief effort. Holden tries to convince Avasarala to release crucial information that might avert catastrophe, but she has her own request of him. As Amos and Bobbie get a little R&R at the station, Naomi has a difficult and long-awaited reunion.

In the thrilling season finale, Inners and Belters fight side by side with the crew of the Rocinante in a last, massive, desperate battle with Marco and his Free Navy, with the fate of the Solar System, the Ring Gates, and of all humanity hanging in the balance.