The season opens with Bobbie Draper and other Martian marines undergoing combat training on Mars. They are deployed to Phoebe Research Station, which had been reported as being attacked. The United Nations debates blockading Martian fleet deployments; Avasarala backs the measure but privately believes that she is being prepared by Errinwright as a scapegoat, and hires private security.
A Martian naval vessel fires on a UN vessel; the UN elects not to fire back, figuring that the Martian missiles were saber-rattling. The missiles pass the UN vessel and destroy Phoebe Station. Draper believes that war with Earth is good; her commanding officer, Sutton, believes war must be avoided. Holden and Miller recover from radiation sickness; Miller and Amos have a violent disagreement that is broken up by Naomi.
The Rocinante crew finds a protomolecule sample among the supplies recovered from the Anubis and decide to hide it in a debris field. Naomi and Holden perform repairs to the Rocinante and their personal relationship deepens. Alex cooks lasagna for the crew of the Rocinante, and over dinner tensions are eased.
This episode contains the following tropes:
- Action Girl: Draper is a model Martian soldier who can beat her own suit of power armor in an arm-wrestling competition.
- Armor-Piercing Question: The Belters who escaped Eros asked if the crew couldn't have saved more. The barb sticks deep in Alex, who will question the human cost of his and the crew's actions several times further on in the season.
- Bait-and-Switch Gunshot: The Martians appear to have fired on a UN warship, but they're actually destroying Phoebe.
- Blood Knight: Draper is a Downplayed Trope example as she's eager to go to war with Earth.
- Broken Aesop: Happens again when Sutton talks about how Mars avoided a war with Earth in the nick of time through diplomacy to talk about the value of peace, only for Draper to state that led to a Space Cold War where Mars was delayed a century in its terraforming efforts.
- Burial in Space: Holden puts Sematimba's corpse in a bodybag and sends him out the airlock.
- Casual Danger Dialogue: Lampshaded by Naomi when she says she misses Holden's tendency to ask irrelevant questions in dangerous situations.
- Coitus Ensues: Holden and Naomi have one of these moments in an airlock.
- Curb-Stomp Battle: The radiation-sickness suffering Miller tries to fight Amos over his dead friend, only to get this to happen to him.
- Danger Room Cold Open: The Squad in combat on Mars turns out to be Draper's team training.
- Daydream Surprise: Holden dreaming he's been infected.
- Destroy the Evidence: Errinwright calls for the UN to send a warship to Phoebe Station as Gunboat Diplomacy, but actually because Jules-Pierre Mao is worried about what they will find. The Martians play into their hands by destroying Phoebe to make sure Earth doesn't claim it.
- Driven to Suicide: Miller contemplates this, which Naomi picks up on.
- Everyone Can See It: Draper's team tease her about being attracted to their CO Sutton, which she bluntly denies, though her Facial Dialogue when she's alone indicates otherwise.
- False Flag Operation: The Conspiracy continues to use this against Mars and Earth to keep their activities secret.
- Fantastic Racism: The Martian troopers all display various levels of disdain and hatred for Earth as well as a desire to go to war. Even one of their own is shown to be sensitive over being teased about having been born on Earth as a child.
- Fanservice: Naomi and Holden remove their space suits after an EVA and have Wall Bang Her sex in the airlock.
- Grave-Marking Scene: Mao places flowers on a tree where his daughter used to play as a child, through he still believes her death was a worthy sacrifice.
- The Heart: Naomi shows her role re this trope when she comforts Miller and Holden.
- Hero with Bad Publicity: Fred Johnson continues to suffer this as the OPA is blamed for the massacre.
- Hollywood Healing: Zigzagged; a subcutaneous injection is enough to stop hard radiation poisoning, though they'll have to wear it the rest of their lives and can't have children. Miller is too weak to fight Amos, yet Holden is strong enough (not to mention being capable enough) to have Wall Bang Her sex.
- I Love Nuclear Power: Lampshaded when Naomi teases Holden that his dose of hard radiation might give him some useful superpowers.
- Knight in Sour Armor: The spy recruited by Avasarala.
- Macguffin: The sample of the protomolecule which the crew recover.
- Morality Chain: Implicitly called out that Amos would be a rampaging monster without Naomi to keep him in check.
- No MacGuffin, No Winner: Mars blows up Phoebe to deny it to the U.N. This proves to be a staggeringly stupid idea.
- Poor Communication Kills: Barely averted when the twenty minute communication gap between Earth and Phoebe nearly leads to all-out war. Fortunately Avasarala is able to talk everyone into waiting for further information.
- Precision F-Strike: Avasarala gets a great one when one of her colleagues tries to explain the communication gap involved in The Big Board."I know how the fucking thing works."
- Reasonable Authority Figure: We see these exist on both sides, but there are also hotheads who would prefer that Earth and Mars go to war, even without an actual conspiracy to make them do so.
- Rousseau Was Right: The Belters and conspirators alike assume that no-one will care about Eros with war brewing, but Errinwright finds himself under pressure from do-gooders on Earth to send aid despite the quarantine.
- The Scapegoat: Avasarala believes she's being set up to take the fall when things go south.
- Shipper on Deck: Draper's friends encourage her to sleep with the CO because it will give them the inside track on what's going on. As she's implied to have genuine feelings for him, she doesn't find this funny.
- Tastes Like Friendship: Invoked by Alex who makes lasagna and insists that everyone eat it around the same table, and discussed with talk of how the mysterious disappearance of confiscated cheese from the Star Helix lockup lead to a short-lived outbreak of neighbourly goodwill on Ceres after it reappeared on the black market.
- Well-Intentioned Extremist: Draper is shown to be obsessing about the Green Mars she will never live long enough to see, and believes that war with Earth is necessary for them to achieve it.
- You Have GOT to Be Kidding Me!: The reaction when the crew listen to Dresden's report, when he concludes that the protomolecule is an extrasolar lifeform.