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The Ending Of The Expanse Season 6 Explained

Caution! There are major spoilers ahead for the series finale of "The Expanse."

The Rocinante has flown its last mission on Prime Video's "The Expanse." Over two networks, one massive fan campaign, and six seasons, the sci-fi series was consistently one of the smartest, most intriguing series on TV. Though it's set hundreds of years in the future and features impressive space battles and advanced technology, the show spoke to today with its depictions of the trials of an oppressed people and the tolls of colonization, and its examination of what happens when humanity attempts to control the unknowable. Through it all, the crew of the Roci came together to form a found family that believed in each other more than they believed in factions or divisions.

In Season 6, the Roci joins the Inner Planets to fight against the Belter terrorist turned rebel leader Marco Inaros (Keon Alexander), whose alliance with a rogue faction of Martians has enabled him to decimate large parts of Earth and badly diminish Mars. During a far too brief six episodes, the war plays out on both personal and universal levels, leading to a nail-biting final battle in a series finale that is far from straightforward. Here, we explain what happened in the final episode of "The Expanse," "Babylon's Ashes."

The Alliance hatches a plan

In the previous episode of "The Expanse," proud Belter Camina Drummer (Cara Gee) agrees to join forces with UN Secretary-General Chrisjen Avasarala (Shohreh Aghdashloo) and the Inner Planets. While Drummer is no friend to the Earthers, she also isn't an ally of Marco. So when Naomi Nagata (Dominique Tipper) shows up to convince her to speak to Avasarala, Drummer agrees, begrudgingly acknowledging that Marco now poses a bigger threat than the Inners she despises.

At the beginning of "Babylon's Ashes," Drummer is meeting with a coalition from Earth and Mars, which also includes James Holden (Steven Strait) and Bobbie Draper (Frankie Adams), representing the Rocinante. Marco's Free Navy is flying toward Medina Station inside the Ring, and the alliance needs to stop him before he reaches the Ring gate. If he makes it there, he'll be able to hide behind the rail guns that were mounted on Medina, enabling him to take control of the universe, including the thousands of planets in the Ring. The Free Navy is split into three battle groups, and the UN and Martians plan to go after the groups with the biggest warships. Drummer and her ragtag Belter fleet are assigned to attack the smaller group, which consists mostly of cargo ships. Meanwhile, the Roci and a strike team led by Bobbie plan to take control of the rail guns at Medina Station so they can turn them on Marco if he gets past the Inners' forces.

The Pella reveals itself

The UNN battle group is heading toward the Free Navy when Avasarala is informed that the intelligence obtained by the Roci has revealed the location of Marco's ship, the Pella. Drummer hears the news that the UNN fleet is planning to engage the Pella over her radio and looks stoic as she turns her attention to the battle group her fleet is targeting. UNN 1 hits the Pella with their torpedoes, and it falls back. But Avasarala notices the Pella doesn't return fire, and the other Free Navy ships aren't falling back to protect it, indicating Marco isn't on the ship.

At the same time, Drummer's fleet engages the freighter in the Free Navy battle group they're fighting. As her fleet fires, the freighter's cargo drops away, revealing the Pella. Marco fires on Drummer, and a fierce gun battle follows. The action briefly knocks Drummer out, and she awakens to find a large hole in the side of her ship, the Tynan. She's informed that her torpedoes are gone, two of her fleet's ships are lost, and the Pella is heading back toward them. Drummer instructs her fleet to disengage and prepares to drive the Tynan into the Pella in a last-ditch effort to stop it, but her ally Walker beats her to it. The impact and its aftermath severely damages the Pella, and Marco's advisor Rosenfeld Guoliang (Kathleen Robertson) perishes. In the aftermath of the battle, Drummer disengages, recognizing there's nothing else she can do.

Bobbie's heroic stand

As the Rocinante burns toward Medina Station, the members of the strike force — including Amos and Bobbie in individual pods — are ejected from Giambattista, an ice hauler. The Roci is hit, and Clarissa Mao (Nadine Nicole) goes to fix the damage but is knocked out as Medina's rail guns fire on the ship. When they reach the vicinity of Medina, the strike team exits their pods. The Roci moves out of range of the rail guns, and Naomi checks on Clarissa, who reveals she's fixed the damage.

Meanwhile, the strike team drops through space in a barrage of bullets. When they land on Medina, they take fire from the ground and air. Bobbie calls the Roci for air support, but the ship can't help as long as the rail guns are still in play. Bobbie orders everyone to fall back as she advances, becoming an assault force of one. She takes heavy fire but manages to take out the rail guns' control center. Just when it looks like she won't make it, Amos arrives to cover her. They are both pinned down, but the Roci appears to provide the air support they desperately need. As the battle ends, Bobbie explains she had no choice but to disable the rail guns. While the original plan was to gain control of them, Bobbie decided it was better to knock them out than enable the Free Navy to keep operating them.

A Martian message

On the Pella, which is still speeding toward the Ring, Marco gets a message from Admiral Duarte (Dylan Taylor), one of the masterminds behind the rogue Martian faction that traded Martian technology for the protomolecule sample and scientist Paolo Cortazar (Carlos Gonzalez-Vio) in the 5th season of "The Expanse." Throughout Season 6, the beginning of each episode shows a snippet of what's happening on the Ring planet Laconia where Duarte settled, but it isn't until Episode 4 that we meet him. Duarte attends the funeral of young Cara's (Emma Ho) brother, and as he speaks to her about the loss, Cortazar informs Duarte that he has finally managed to communicate with the dormant alien spacecraft hovering above the planet.

At the beginning of "Babylon's Ashes," Duarte looks up at the sky smugly, seemingly indicating he's confident that he's now harnessed the protomolecule's power. And as Duarte's message to Marco makes clear, that means he no longer feels he owes Marco or the Free Navy anything — including the Laconian weapons Marco requested for the battle the Free Navy is in the middle of waging. Duarte's message is a massive kiss-off, as he not only denies Marco the weapons but also warns him to stay away from the Laconia system entirely. As Duarte tells him, Marco was a "useful distraction," but now he has "gods to kill." Yikes! Unfortunately, since this is the show's final episode, we won't get to see how Duarte's quest turns out.

Naomi proposes a Hail Mary

While Marco's relationship with Laconia has been severed, he's still about to win the war against the Inners and is already making plans for when he recaptures Medina Station. Only the Roci stands in his way. The crew tosses around ideas to stop him even though they know they don't have enough firepower to do so. However, Naomi comes up with an idea that could end Marco permanently.

Earlier in the season, Holden notices that some ships disappear without a trace as they pass through the Ring. In Season 5, he tells Fred Johnson that whenever he goes through the Ring, he feels angry entities lurking inside. He believes these are the aliens that created the Rings and took out the civilization that made the protomolecule. Holden thinks humanity is waking up these malevolent beings by going through the Rings now. In the penultimate episode of Season 6, Holden's investigation into the ships that vanished in the Rings leads him to Season 4's Dr. Okoye (Lyndie Greenwood), who tells him that the disappearances are preceded — or might be triggered — by a "mass energy threshold."

Naomi realizes they can use this information against Marco and the Free Navy. If they can push as much mass as possible through the Ring at exactly the right time, they can reach the energy threshold to trigger the Ring entities. The Ring entities will then lash out at Marco's ship, putting a stop to him once and for all.

Deciding on a way forward

Naomi's plan works perfectly, and though she deeply mourns the loss of her and Marco's son Filip (Jasai Chase-Owens) — whom she believes was on the Pella with his father — she and the crew of the Roci manage to bring Marco and the Free Navy to an end. This leaves the leaders of Earth and Mars and those in the Belt who aren't loyal to Marco to negotiate a truce. Along with Avasarala and Mars' prime minister, Drummer represents the Belters in the talks. Holden is also at the table as the one Earther who is a friend to all sides. All parties agree they need to form a transport union to control trade to the Ring colonies, but the Belters want control, as they believe Earth and Mars will eventually go back to their old oppressive ways.

None of the factions will budge, so Holden points out that if they can't find a way to trust each other now, they never will. This gives Avasarala an idea: The transport union could be an independent agency with Holden — someone Earth, Mars, and the Belters trust — as its leader. Holden is surprised by the idea but ultimately says he's open to it if he can have certain assurances.

Holden makes a bold move

The scene cuts to the ceremony on Medina Station announcing the formation of the transport union and Holden as its president. Holden makes a speech expressing his pride in being the first head of the new organization as Avasarala and Drummer, the union's vice president, stand on either side of him. The teleprompter indicates his speech is coming to an end, and Avasarala moves to congratulate him, but Holden keeps talking. There's an audible gasp as he resigns as the leader of the transport union and introduces Drummer as the new president — to the joy of the Belters present.

Drummer steps up to the podium to answer questions as Holden walks away and is confronted by a furious Avasarala. She accuses him of negotiating in bad faith and says she'll undo his actions, but he begs her not to, convinced he's done the right thing. Ultimately, Avasarala backs down and smiles as the pair shake hands.

A last-minute revelation

Later, Holden and the crew are back on the Roci, where Bobbie has joined them as their new pilot. When they're alone, Holden acknowledges to Naomi that he made a lot of people angry by stepping down from the transport union. She reassures him he did the right thing and gives a speech about helping people and small actions making big impacts. As she talks, the story flashes back to the Pella before it entered the Ring.

Marco had just given a rousing speech to the crew's cheers, but Filip isn't enthralled like the others. His brief exposure to his mother's perspective in Season 5 opens his eyes to just how manipulative Marco can be, and throughout the 6th season, Filip becomes increasingly convinced Marco may not be doing the right thing. The last straw comes when Marco dismisses Rosenfeld's death and indicates he and Filip made a choice to be in their current situation. Of course, Filip had no choice, so as Marco distracts his minions with pretty words, Filip takes a ship and flies away from the Pella and his father. Most tellingly, when designating himself as the ship's owner, he types in the name Filip Nagata, taking Naomi's last name instead of Marco's.

On the Roci, Holden starts brainstorming their next moves, but Naomi interrupts him, asking him to take a breath before they begin a new adventure. This brings the show to a quiet end that's still bursting with possibilities.