"Babylon's Ashes" is the sixth episode of the sixth and final season of the American science fiction television series The Expanse. It originally premiered on Amazon Prime in the United States on January 14, 2022, written by Daniel Abraham, Ty Franck, and Naren Shankar, and directed by Breck Eisner. The episode title draws its name from the sixth The Expanse novel of the same name written by James S. A. Corey, the joint pen name of Abraham and Franck.

Showrunner Daniel Abraham had announced in 2020 that Season 6 was the ending of the series while noting in later interviews that further seasons could happen, pointing out that there were three more existing books to adapt material from.

"Babylon's Ashes" continues the events of the previous episode, wherein the Inners (residents of the inner planets of the Solar System) and Belters (residents of the asteroid belt's various mining groups) join the crew of the Rocinante in a desperate, high-stakes battle against Marco Inaros and his Free Navy.

The series finale has met with largely positive reviews.

Plot On Laconia Cara's (Emma Ho) parents are horrified when they discover she used the strange, dog-like creatures in the wilderness outside of the colony to resurrect her dead younger brother Xan (Ian Ho), who returns home visibly infected by the protomolecule. Cara's father confirms his fears by watching in horror as Xan immediately heals from a knife wound, and decides to notify the soldiers. Cara and Xan flee into the woods, with Xan pondering why his parents were afraid of him.

The Free Navy Aboard the Pella, Marco Inaros (Keon Alexander), fools Camina Drummer's (Cara Gee) Belter attack fleet into attacking the wrong ship and uses the resulting misdirection to cripple Drummer's fleet. As the Pella starts to move away, Drummer prepares to crash her ship into it in a suicide mission that would destroy them both. Liang Walker (Stuart Hughes) does so in her stead, his destroyed ship badly damaging the Free Navy flagship.

Fleeing to the Ring, Inaros contacts the renegade Martian Admiral Duarte (Dylan Taylor) on Laconia, but Duarte denies the Free Navy refuge, rearmament or repair from Laconia. He curtly dismisses Inaros, saying he is busy, having gods to kill.

The Rocinante In an attempt to wrest control of the rail gun emplacements on the Ring, the ship uses a remote-controlled ice freighter, the Giambattista, to deliver multiple strike teams to the Ring Station amidst a screen of several hundred decoy cargo containers. Most teams land on the station successfully, but become overwhelmed by the withering firepower of renegade Martian troops stationed to protect the rail guns. Bobbie Draper (Frankie Adams) single-handedly destroys the power source for the rail guns, rendering them inert, and the Rocinante wipes out the remaining Free Navy fighters.

Knowing that Inaros' Free Navy fleet is on its way, Naomi Nagata (Dominique Tipper) suggests that instead of trying to mount a counter-attack, they instead concentrate on awakening the entities dormant within the Ring. Believing she is also killing her son aboard the Pella, she momentarily hesitates before detonating the Giambattista's energy core, serving as the catalyst that awakens the Ring entities which waste no time in obliterating Marco Inaros and his ship. Nagata is overcome with guilt, knowing that while she has ended the war, she believes she has ended the life of her only son in doing so.

Bobbie becomes the new pilot for the Rocinante. Clarissa Mao (Nadine Nicole), discovering that the enhancements she had received have considerably shortened her life, chooses to remain aboard the ship as a mechanic under Amos (Wes Chatham). Holden and Nagata remain together, enjoying their hard-earned moment of peace.

The Transport Union The representatives of Earth, Mars and the Belter Union gather to discuss the formation of a transport union to deal with trade headed to and from the Ring, but the Belters, led by Drummer, balk at potentially being constantly outvoted in any substantive decision-making by the Inners. Holden points out that Inaros's success was built on his recognition of the Belters' fear that the fruits of the future would always be held back from them; he adds that the war will only truly end once this fear has been put to rest. Earth's Secretary General Chrisjen Avasarala (Shohreh Aghdashloo) proposes that the transport union be independent, based at Medina Station and led by someone without allegiances to any faction; she nominates Holden because he is respected by Earth, Mars and Belters alike. He reluctantly agrees, but upon taking office, he immediately resigns and appoints Drummer in his place, thus giving the Belters effective control of the Ring traffic to ensure their independence.

Before the episode fades to end credits, the viewer sees the Ring alone in the darkness of space, with occasional, and increasing, ripples of red. A faint blue outline of Duarte's protomolecule warship station can be seen in the center of the Ring.

Production The episode, entitled "Babylon's Ashes", was written by show creators Daniel Abraham, Ty Franck, and Naren Shankar, using the same title as the sixth book of the novel series, and directed by Breck Eisner. It is the sixth episode and 62nd overall episode of the series, serving as both the season and series finale. The episode itself, which draws upon both the sixth book as well as the 2017 novella by the same author, Strange Dogs, was filmed at the same time by Eisner.

During a New York Comic Con panel discussion alongside members of the cast, Shankar noted the difficulty of adapting the amount of detail from the sixth book and the novella, which translated to each episode being intense. "You never feel like you’re letting your foot off the gas pedal. By the time you get to the end, it feels cathartic." Franck and Abraham noted that every script was written with "no fat" in it, no extraneous material.

During that same panel, Wes Chatham noted that the addition of Nadine Nichole's character Clarissa Mao serves as a way for Amos to reflect on his own growth as a person. "Amos has always sought out these mentors that he's believed in to make moral choices and give him guidance in life, but he has grown to the point that he's become that to Peaches," Chatham said. "Now that he has someone who's looking to him and leading her in a way, he's starting to think about what their mission is... and why we are involved in these massive big movements in history."

Craig Elvy of Screenrant noticed that a pattern of using the name of the novels from which each of the season was drawn upon as the title for the last episode of the season. Elvy believes that season 6's investment into the development of the Laconia plotlines will extend beyond the series' conclusion. He notes that the camera's final focus on the Ring, with the distinctive red flashing increasing, seems to confirm "Holden's fear that the alien presence would keep growing stronger"; he further points out that, near the center of the Ring, the outline of Admiral Duarte's protomolecule warship station can be seen.

After Amazon Video has announced that the sixth season would be its last, Polygon writers Petrana Radulovic and Clayton Ashley presumed that since season 5 covered the material in the fifth book Nemesis Games, "it makes sense that the series would conclude... otherwise, the show would need to cover not only the (seventh through ninth books), but also account to a thirty-year time jump between books six and seven."

Over a year later, fellow Polygon writer Charlie Hall interviewed Authors Daniel Abraham and Ty Franck – who collectively wrote The Expanse novels using the pseudonym James S.A. Corey – preferred to think of the series as "at a very natural pause point" for the story, considering the idea of being canceled as "outmoded".

Director Breck Eisner, who had directed 14 episodes of The Expanse over its six seasons considers the paradigm for the look of the sixth season sets to be a submarine war film. "Before we start, sometimes I go through movies and pull footage of inspirational clips. I did that this year with Das Boot and other sub movies to try and emulate the looks of the lighting and the characters' ragged appearance... cramped spaces and the idea of this feeling of the walls closing in on you."

To emphasize the aforementioned claustrophobic feel, the set piece the assault team's descent to the Ring Station took place inside of cargo containers; Franck and Shankar describe them as "Porta Potties dropped out of space". The people hidden inside amongst the hundreds of containers heading to the Ring station not being able to see or know what was occurring before the sides of the container break away, which created a WW II paratrooper moment. Speaking to the technical aspects of the scene, Eisner described that they used a motion-controlled camera which tracked Wes Chatham's Amos on a crane as he 'descended'; by moving the crane up and the camera down, they were able to overcome the technical difficulties of the set piece. The resulting tracking shot has Amos suddenly drifting through space, cringing and moving to avoid aerial fire occurring all around him. Eisner praised Chatham's performance, noting "he really sold it."

In his interview with showrunner Naren Shankar, Entertainment Weekly reporter Dalton Ross, Shankar explained that at the beginning of the series, Earth, Mars and the Belt were practically at war with each other. "And all it would take is a spark... we then provide the spark", referring to the introduction of the mysterious protomolecule. The showrunner points out that the events and conclusion of season six develops and delivers a resolution for that friction. Shankar also points out that, if the viewer watches the end credits very closely, "we even put a little something in there. If you notice, the Ring entities are sort of coming to life at the very end."

Easter egg Reviewers were quick to notice a major easter egg within the episode. During the Rocinante's attack on the Ring's rail gun emplacements, the names of several prominent characters from science fiction books, television and film were listed on a video screen depicting the various members of the strike team. Among the names listed were as follows:

Alpha Team: Gial Ackbar from Star Wars: Return of the Jedi; Douglas Quaid from Total Recall; David Bowman from 2001: A Space Odyssey; Commander Shepard from Mass Effect; Duncan Idaho from Dune; Alex Rogan from The Last Starfighter; Jason Nesmith from Galaxy Quest and Edward Buck from Halo.

Bravo Team: Shaenon K. Garrity, a sci-fi author and webcomic creator; Ellen Ripley, Dwayne Hicks, Hudson and Vasquez from the Alien films; Joseph Cooper, from Interstellar; John Anderton from Minority Report; Rick Deckard from Blade Runner and Jack O'Neill from Stargate.

Charlie Team: Lucky Starr, a character from the Isaac Asimov book series of the same name; Louise Banks from Arrival; Kevin Flynn from Tron; Ron (sic) Neary from Close Encounters Of The Third Kind; Johnny Rico from Starship Troopers; Kara Thrace from Battlestar Galactica; Sarah Connor, from the Terminator; Ryan Stone from Gravity and William Riker from Star Trek: The Next Generation.

Post-production podcasts