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. 

A controversial decision puts Holden at odds with his crew; on Ceres, Avasarala struggles to contain an escalating humanitarian crisis; Drummer's growing faction stage a daring raid; Filip makes an unexpected discovery. 

Drummer arrives on Ceres to aid the relief effort; Holden tries to convince Avasarala to release crucial information that might avert catastrophe; Amos and Bobbie get a little R&R; Naomi has a difficult and long-awaited reunion. 

Inners and Belters fight side by side with the crew of the Rocinante in a last 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.