'The Expanse': Here's a recap of Season 4 ahead of Season 5 on Amazon Prime Video

It's safe to say that "The Expanse" has well and truly earned its place in the Sci-Fi Hall of Fame. Like many other members of this clique of quality, it has a story arc structure rather than an episodic one — and quite a complex story arc at that. Plus, it's been 12 months since we last saw the Rocinante roaring through space on our TV screens. 

While last year's fourth season was a simultaneous 10-episode drop, Amazon Prime Video is taking a different approach with Season 5 by making the first three episodes simultaneously available — it drops Dec. 16 — with the following seven episodes will air week by week. 

So, before you start watching the fifth season of "The Expanse," here's our handy guide to all the key events that took place in the last season of the show. If you're catching up from even earlier, check out our recap of seasons 1-3 here.

Related: How Amazon (and Jeff Bezos) Saved 'The Expanse'

Background

Set a little over 300 years in the future, around 2350, humans have colonized space and three major factions have developed in the solar system: Earthers — governed by the United Nations (UN), Martians and the Belters. 

The Earth itself has changed drastically and we see that sea levels have risen by 20 or 30 feet and the colony on Mars declared independence some time ago. To quote Franklin Degraaf from "Remember the Cant," (S01, E03) "You know what I love most about Mars? They still dream. We [Earthers] gave up. They're an entire culture dedicated to a common goal, working together as one to turn a lifeless rock into a garden. We had a garden and we paved it."  

The former MCRN Corvette-class light frigate, now known as the Rocinante, has established itself as a sci-fi fan's favorite. (Image credit: Amazon Studios)

The Belters are a breakaway faction that has made the asteroid belt between Mars and Jupiter their home. They are the descendants of the first workers — the miners, the builders, the engineers — who went out to help build the infrastructure in the solar system. However, after their bodies changed they were physically unable to return to Earth and subsequently oppressed by the Inners, who they are dependent upon for food, water and air. In contrast, all Earthers have a universal basic income, plus food, water and air is abundant and freely available. 

Conditions on the space stations and hollowed-out asteroid colonies are a long way from ideal, and the low gravity conditions to which they have adapted mean that most can never even visit Earth, because their bodies wouldn't be able to adjust to the increase in gravity. In the Belt, air and water are more precious than gold. Then there's the Outer Planetary Alliance (OPA), which started its life as a labor union or advocacy group, fighting for the interests of the Belters, and depending on who you ask, it's known as both a sociopolitical movement and a terrorist network.

Related: 'The Expanse' is getting a new comic book miniseries: A first look

On Ilus IV

Following the mysterious construction and discovery of the "ring" — a wormhole network that connects planetary systems across the Milky Way galaxy — a new interplanetary "gold rush" has begun. Potential settlers swarm to the area and newly appointed United Nations Secretary-General Chrisjen Avasarala (Shohreh Aghdashloo) and the Martian Parliament, concerned with potential unknown dangers, orders a blockade of the space surrounding the alien device, 

It's not universally popular and Cabinet Minister Nancy Gao (Lily Gao) sees the ring as an opportunity to solve the massive unemployment and overcrowding problems of Earth and to give many people a chance to claim their "160 acres." However, a convoy of Belter refugee ships from Ganymede attempts to run the blockade and one called the Barbapiccola gets through and lands on an unknown planet and claims it as their own, they name it Illus after the brother of the mythological figure of Ganymede.

The "ghost" of Detective Miller (Thomas Jane) who now refers to himself as "the Investigator," is a great character carried over from the first season. (Image credit: Amazon Studios)

Avasarala sends Jim Holden (Steven Strait) there as her envoy, along with the rest of the Rocinante crew, in order to identify and assess any potential protomolecule exposure and because the conditions are similar to Earth, Naomi Nagata (Dominique Tipper) must begin medical treatment while en route to condition herself to 1G. Meanwhile, the OPA begins transitioning the Behemoth under the command of Camina Drummer (Cara Gee), now renamed Medina Station, to become outpost and gatekeeper to humanity's new frontier.

Beltalowda! Cara Gee opens up about Drummer's emotional odyssey in 'The Expanse' season 5

The Earth ship Edward Israel, ferrying a Royal Charter Energy (RCE) expedition backed by Earth, sends a shuttle to Ilus that is destroyed during its landing as a result of sabotage of the landing pad. Many lives and supplies are lost. 

The UN's Royal Charter Energy (RCE) is instructed to explore worlds though the Gate and takes the old colony ship the Edward Israel through the Ring to Illus, they do not recognize the Belters claim to the planet and dub it "New Terra." As they attempt to land the first survey teams, a group of Belters destroy the landing pad causing the Shuttle to crash killing many RCE members including the expedition leader and the loss of many supplies.

The Rocinante crew arrives amid tensions between the surviving shuttle passengers and the Belter settlers that escalate into an armed standoff, which is interrupted when a swarm of alien "bugs" attacks the settlement. Security Chief Adolphus Murtry (Burn Gorman), who was wounded in the shuttle accident, takes control of the expedition determined to prove the shuttle was destroyed by sabotage and to remove the belters from the planet by any means. Holden sends Amos to assist Murtry while he and Alex travel towards some strange, alien  "Prometheus"-esque towers to try and find any trace of the protomolecule.

Amos Burton (Wes Chatham) and Murtry go to the landing pad, where they confirm that the shuttle crash was as result of a deliberate attack by the Belters from the Barbapiccola. Holden and Alex Kamal (Cas Anvar) along with Dr. Elvi Okoye (Lyndie Greenwood), an RCE Scientist, investigate the “towers.” Guided by a "ghost" of Detective Miller (Thomas Jane) who refers to himself as "the Investigator," Holden and Alex enter the alien structure near the settlement. Holden removes a root growing through a panel, at the behest of the Investigator, activating the structure and triggering a pattern of lightning strikes across the surface of the planet.

Amos and Naomi help repair the damaged power generator and Murtry identifies the Belters responsible for the sabotage of the landing platform and orders their execution. The Belters naturally react badly to the murders and Naomi tries to help Dr. Lucia Mazur (Rosa Gilmore), a Belter complicit in the sabotage, escape from Murtry's retribution. Holden, accompanied by Alex and Dr. Okoye, finds another alien structure that was activated; it's displacing wide swathes of ground while moving toward the settlement. Despite Okoye's protests, Holden has Alex destroy the structure with a torpedo from the Rocinante.

The ongoing tensions between the Belters and the RCE escalate in the camp and amid the tension, Murtry kills a Belter. This leads to a dangerous standoff, which is interrupted by lightning striking the settlement, damaging the Belters' power generation infrastructure. Murtry orders the Earthers not to help the Belters. 

Naomi takes Lucia to the Rocinante and they are ambushed, Murtry shoots them and hits Lucia, but Holden arrives and is able to get them safely onboard. Murtry eventually backs down when Holden and Alex intervene and fire the Rocinante's point defense cannons (PDC) at his forces. Naomi, Alex, and Lucia go into orbit aboard the ship while Holden remains on Ilus.

Camina Drummer (Cara Gee) is now in command of the Behemoth, now referred to as Medina Station, guarding the ring space (Image credit: Amazon Studios)

In an attempt to convince all the settlers to leave Ilus, Holden reveals that he has inadvertently reactivated the alien technology, but this only worsens an already tense situation. Strange and unexplained events continue to take place on the surface as an island on the other side of planet explodes, causing a shockwave to begin rolling over the planet's surface. Not far behind the shockwave is a tsunami that will destroy the settlement and submerge a third of the continent. The settlers finally consent to evacuate Ilus after Holden agrees to vouch for their claim on the planet to the UN. Once again, this puts Holden at odds with Murtry and the RCE, nevertheless Murtry arranges for one of the Edward Israel's two remaining shuttles to assist in the evacuation.

The explosion on the surface is coinciding with more protomolecule activity in the orbit of Ilus and this disables the fusion reactors on all orbiting ships, including the Rocinante, the Barbapiccola and the Edward Israel and destroys the shuttle as it's entering the atmosphere, stranding everyone on the surface.

They are forced to take shelter in the alien tower structure, but many of those still at the settlement are killed as the shockwave hits. Holden and Okoye finish evacuating everyone into the structure and close up a makeshift water barrier before the surrounding area is flooded.

Inside the alien structure the Earthers and the Belters set up separate camps, tensions are high and then, after a RCE guard is found dead, they discover an extremely toxic "death slug" that inhabits the tower with them and a single touch is fatal. To make matters worse, people are starting to lose their vision as they've been infected with microorganisms that are growing in their eyes — but Holden seems to be immune. Okoye determines that the microorganisms will cause blindness and the situation begins to get progressively worse, not helped by the dwindling lack of supplies and medical resources. Soon, everyone is blind except for Holden.

Secretary General Chrisjen Avasarala (Shohreh Aghdashloo) conducts a military funeral for the UN Marines who died in the attack on the Pizzouza. (Image credit: Amazon Studios)

Inside the alien structure the Earthers and the Belters set up separate camps, tensions are high and then, after a RCE guard is found dead, they discover an extremely toxic "death slug" that inhabits the tower with them and a single touch is fatal. To make matters worse, people are starting to lose their vision as they've been infected with microorganisms that are growing in their eyes — but Holden seems to be immune. Okoye determines that the microorganisms will cause blindness and the situation begins to get progressively worse, not helped by the dwindling lack of supplies and medical resources. Soon, everyone is blind except for Holden.

Running out of options, Okoye tests Holden's optical vitreous humor and finds precancerous cells. She determines that Holden is immune because of his anticancer medication, which he has been taking since absorbing radiation on Eros in the first season episode "Critical Mass" (S01, E09). Okoye prepares a cure and everyone affected regains his or her sight.

In orbit, without fusion reactors, there is no way for the ships to leave. The Rocinante has reserve power for several months but the older, slower Barbapiccola is starting to drag on the atmosphere and will burn up in approximately one day.

The crews of the Rocinante and the Barbapiccola successfully tether their ships to one another in an attempt to tow the older ship to a higher safer orbit. Murtry meanwhile, has the Israel launch a weaponized shuttle at the Rocinante, but Alex destroys the shuttle with a PDC. 

The protomolecule's construct of Miller leads Holden to a portal within the alien structure that enables them to travel to another location on Ilus and there, they find a giant energy circle. Miller, who can now overcome his protomolecule programming for short periods, warns Holden about what lurks within the planet they are on and that this is "the eye of an angry God."

The crew of the Rocinante arrive on Ilus as Naomi Nagata (Dominique Tipper) struggles with full gravity. (Image credit: Amazon Studios)

Murtry and his second-in-command, Chandra Wei (Jess Salgueiro) follow Holden through the portal, determined to kill him. They themselves are followed by Amos and Okoye. Wei confronts Amos (don't forget these became involved while they were in the settlement). When neither stands down, Amos doesn't hesitate to kill Wei, but Murtry shoots and disables Amos.  

Holden confronts Murtry and shoots and disarms him as Okoye helps Miller, now inhabiting a protomolecule construct, to reach the energy circle, through which they then fall. This neutralizes the effects of the alien technology on and around the planet, which means the Rocinante and the other ships in orbit can use their fusion drives once again

Murtry and Amos are brought onto the Rocinante and recover. Murtry and Lucia are to stand trial, but Holden sets Lucia free. The Belters and the RCE science team decide to stay on Ilus, planning to rebuild the settlement together and continue research. While the Edward Israel remains in orbit, the Rocinante and the Barbapiccola head back to the solar system.  

On Mars

During her state visit to Mars, Avasarala invites Bobbie Draper (Frankie Adams) to a state banquet. (Avasarala and Draper bonded during their escape from Jules Pierre-Mao onboard the Razorback and their time together on the Rocinante.) 

Draper has been dishonorably discharged from the Martian Marine Corp and is now working in a shipyard scrapping newly redundant Martian Congressional Republic Navy (MCRN) ships and finds herself ostracized by many within the MCRN for her actions, as well as her friendship with the UN Secretary-General, one of the MCRN's historic adversaries.

Ilus was designed to be a single, massive refinery by the Ring Builders approximately 2 billion years ago. (Image credit: Amazon Studios)

Bobbie discovers that her nephew, David (Kolton Stewart) is selling illicit "focus drugs" for a gang. At the behest of his "girlfriend" LeeLee (Dayle McLeod) she ends his involvement by pummeling the gang members. In retaliation the gang kidnaps David to force him to work off the debt incurred when she destroyed the shipment of drugs he was carrying. 

Turns out that the operation is being run by a corrupt cop, Detective Esai Martin (Paul Schulze). He agrees to release David but only if Bobbie helps them steal military equipment from where she works. Reluctantly, she complies and leaves a secure door unlocked, allowing a pair of Belters to steal some high end Martian communication equipment.

Bobbie Draper (Frankie Adams) has a close call when the shipyard dome above her explodes on Mars. (Image credit: Amazon Studios)

Bobbie attempts to report the theft to her supervisor, only to find out that he himself is interested in selling stolen goods. She quits in disgust, but shortly after, she is arrested for "abetting the crime." However, her charges are dropped once she accepts Martin's offer.

The next heist is to steal mothballed terraforming tech, but their inside man fails to get them past a crucial security door, so Bobbie dons an environment suit with low oxygen, climbs a maintenance tower and manually disables the door's hydraulics. Unfortunately, a watchman is on site and manually overrides the airlock, preventing Bobbie from getting back inside. She passes out, but awakens shortly after to find Esai and LeeLee had subdued the guard and pulled her inside. Esai is impressed with Bobbie's performance and the two form a mutual respect of sorts.

Bobbie visits Esai's home to raise her concerns, about the nature of the next job, but he dismisses them and validates his criminal activities, despite being a cop, as being the only way he can properly support his family and he explains that the dream of Mars is over, no-one is going to want to spend their lives terraforming a planet when there are countless worlds through the ring gates, where they won't have to live in domes and can breath real air and see a real ocean.

Bobbie is able to confirm that it's a trap, but fails to prevent an ambush in which everyone is killed aside from LeeLee, as Bobbie chases after the assailants she catches sight of a Belter just before he detonates a bomb destroying the shipyard dome, forcing Bobbie and LeeLee to flee while the Belter escapes with a large stash of stolen Martian tech.

On Earth

Avasarala is blindsided while on a visit to Mars as Gao announces her resignation in order to run against her in the election for Secretary-General of the U.N.

Their first public debate does not go well for the current Secretary-General, but it's cut short when an unidentified ship claiming to be a damaged civilian vessel is detected heading toward an Earth asteroid defense platform. Once it's been identified as the Sojourner, a ship allegedly destroyed by OPA pirates, Avasarala orders its destruction.  

Leader of the "Tycho" faction of the OPA, Fred Johnson (Chad Coleman), leaks information — that he believes to be true — to the U.N. that Inaros is onboard the Pizzouza and Avasarala orders a team of marines to board it and capture Inaros alive. However, the operation does not go according to plan and a firefight breaks out, resulting in the ship exploding and the deaths of everyone onboard.

The man on the left is about to get seriously done over by the man on the right. And he thoroughly deserves it.  (Image credit: Amazon Studios)

In response, General McCourt (Benz Antoine) resigns, accusing Avasarala of putting political gain over the lives of the marines under his command. Despite an attempt to smear her with allegations about her past, Gao wins the election, opening the floodgates for settlers to travel through the Rings. Avasarala pays a heavy price in her personal and political life, and Bobbie informs her of Martians trafficking military weapons together with Belters and she accepts an offer to work with Avasarala.

In the Belt

Camina Drummer, played by actress Cara Gee.  (Image credit: Amazon Studios)

The OPA begins transitioning the Behemoth under the command of Camina Drummer (Cara Gee), now renamed Medina Station, to become outpost and gatekeeper to humanity's new frontier, a little bit like Deep Space Nine.

Drummer and Ashford are keen to keep the peace with the Inners, but unsanctioned piracy against ships waiting to pass through the ring continues. They apprehend Marco Inaros (Keon Alexander) who is responsible for the murder of the passengers of the U.N. Navy colony ship Sojourner. It was held at the ring blockade for 13 weeks waiting for permission to enter, but it was attacked by Belter pirates, who spaced everyone onboard to send the message that the Belters do not forget the 100 years of abuse at the hands of the Inners.

While being questioned by five OPA faction representatives onboard Ashford's ship, the Tynan, Inaros criticizes the truce and appeals to Belter solidarity. Ashford and another representative vote to sentence Inaros to death, the two other representatives vote to acquit him. Drummer — with the deciding ballot — also votes to acquit and release him to maintain OPA unity.

Drummer resigns from her position, upset over Johnson giving the evidence to Earth, as it played into Inaros' scheme of creating trouble for the U.N. and stirring up tensions. Ashford plans to independently hunt down and kill Inaros, but Drummer, still weary of the political implications, declines Ashford's offer to join him. 

The death of Commander Klaes Ashford (David Strathairn) was one of the most tragic events in the whole of Season 4. (Image credit: Amazon Studios)

Ashford continues his hunt for the Inaros and during an interrogation of a Martian Naval Supplies Officer, he learns of a much larger conspiracy. 

Ashford finds Inaros and boards his ship, but he's ambushed by Filip (Jasai Chase-Owens), the son of Inaros…and Naomi. Ashford secretly records his conversation with Inaros, managing to send it out as a message before Inaros makes him walk the proverbial plank out an airlock. 

Inaros launches asteroids cloaked with Martian stealth technology saying, "They'll never see it coming." 

And now you're all caught up on "The Expanse" Season 4 and are ready to launch back into space with Season 5. 

Seasons 1 to 4 of "The Expanse" are available to watch now on Amazon Prime. Episodes 1 to 3 of Season 5 are also now available on the streaming service.

Follow Scott Snowden on Twitter @lorumipsum. Follow us on Twitter @Spacedotcom and on Facebook.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

Scott Snowden

When Scott's application to the NASA astronaut training program was turned down, he was naturally upset...as any 6-year-old boy would be. He chose instead to write as much as he possibly could about science, technology and space exploration. He graduated from The University of Coventry and received his training on Fleet Street in London. He still hopes to be the first journalist in space.