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If You Aren't Watching The Expanse, the Best Scifi Show on TV, Here's What You Need to Know to Start Tonight

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It’s been a year since The Expanse’s tense season two finale, and we are deliriously excited for the season three premiere tonight on Syfy. You should be, too. The scifi series is strong on every front: a thrilling story equally packed with political intrigue and tons of space action; fascinating and well-written characters; and gorgeous special effects. But if you’re finally ready to start watching the series, there’s a good deal that you should know. We have you covered, of course.

This also works equally well as a refresher for those whose memory of where the series left off might be a bit dusty—after all, a lot of shit hit the fan at the end of last season. Either way, here’s all you need to know to get up to speed on the best scifi show on TV.


Here’s the deal

The Expanse is based on the scifi novel series by James S.A. Corey, the pen name of author duo Daniel Abraham and Ty Franck. It’s set some 200 years in the future, when technology—especially the Epstein Drive, a fusion drive that enables efficient, long-range space travel—has allowed humans to colonize Mars as well as the asteroid belt. When The Expanse begins, long-simmering political tensions between Earth (still outwardly lush and gleaming, but sagging under serious infrastructure problems) and Mars (which has prioritized its military over its terraforming efforts) have pushed both sides to the brink of war. Meanwhile, the various factions of rough-hewn Belters, as they’re known, agitate for their rights under the aegis of the Outer Planets Alliance, which is viewed by many on Earth and Mars as a terrorist group.


The show follows a diverse array of people from across the solar system, all of whom struggle with tough choices as part of their survival. Turf wars are one thing, but the unstable situation becomes way more complicated after the discovery of the alien “protomolecule” on one of Saturn’s moons. At first, the protomolecule seems like just a terrible new plague—anyone who touches it is guaranteed a slow, agonizing death. But as The Expanse’s plot thickens, it soon becomes apparent that the substance’s unknown origins mean its capabilities extend way beyond the realm of human comprehension. That doesn’t stop sinister corporation Protogen (Earth-based, but working for the highest bidder) from immediately trying to weaponize it, first by unleashing it on thousands of unsuspecting Belters living and working on the asteroid Eros—and later by using it to turn a group of specially-selected children into terrifying “hybrid” supersoldiers.

By the end of season two, the existence of the protomolecule is no longer top-secret, and the stuff has become so widespread that wiping it out of existence is no longer possible. It’s so inescapable, “it’s part of the equation now,” as one of the characters points out in the season two finale. It has so far been the driving force behind every plot thread—what is it? Who has it? Where did it come from? What can it do? Oh fuck, what’s it doing now?—though the stakes vary depending on who’s involved.


Who’s who

R.I.P. First, we must mention two important characters who presumably met a fiery end when Eros, transformed from asteroid into giant missile by the protomolecule, smashed into Venus: Miller (Thomas Jane), a Belter and former police detective, and Julie Mao (Florence Faivre), the missing person he’d been hired. Though Julie was born a rich Earther, she joined the OPA in defiance of her father, slippery Protogen chief Jules-Pierre Mao (François Chau), and worked to expose his company’s plans for the protomolecule. While tracing her last known movements around the Belt, Miller—a hard-drinking, cynical loner—unexpectedly falls in love with her. Though she succumbs to the alien pathogen before they ever get to meet in person, he’s able to connect with her consciousness through the protomolecule (like we said, its capabilities extend way beyond the realm of human comprehension), and convinces her to steer Eros into Venus instead of its original target, Earth—thereby saving billions from annihilation. A sanitized version of their love story turns them into folk heroes around the Belt, though the loss of his daughter does nothing to change Jules-Pierre’s diabolical scheme.


The Rocinante crew Originally thrown together as co-workers on the doomed ice hauler Canterbury, Captain James Holden (Steven Strait), pilot Alex Kamal (Cas Anvar), engineer Naomi Nagata (Dominique Tipper), and mechanic Amos Burton (Wes Chatham) bond after surviving the one-two destruction of the Cant and then the Donnager, the Martian ship they encountered immediately after. After barely escaping both disasters—both caused, it’s later learned, by Protogen-affiliated stealth ships—in a Martian warship (later rechristened the Rocinante), and unwittingly finding themselves at the center of an interplanetary powder keg, they accept help from Fred Johnson (Chad L. Coleman), the head of the OPA-controlled Tycho Station. Though they’re a mixed group of Earthers, Martians, and Belters, and they butt heads a lot, they’re ultimately more loyal to each other than to any particular political faction. Each Roci crew member has their flaws, some more serious than others, but by the end of season two they’ve sort of all come around to Naomi’s declaration that “We have to do good where we can, when we can.” If that means breaking some laws here and there, well then so be it.

As luck (or not) would have it, they were among the first people outside of Jules-Pierre Mao’s organization to know about the protomolecule, having encountered it while searching the ship that helped get Julie Mao to Eros. That links them to Miller, who becomes a contentious member of their team for several episodes—and since the show’s overarching story is focused on the protomolecule, it makes them key players in The Expanse’s ongoing intrigue.


The botanist The newest arrival on the Rocinante is Prax Meng (Terry Chen), a mild-mannered botanist and single dad whose low-key life on agricultural outpost Ganymede was completely shattered when a battle between Earth and Mars devastated the station. He links up with the Roci crew after realizing he knows a doctor who’s got ties to Protogen’s black-ops division; he agrees to help them track the man down while he looks for his missing daughter. But while he’s searching for the girl, he realizes she’s been kidnapped into the human-protomolecule hybrid project. His quest to rescue her before she’s transformed into a terrifying supersoldier will no doubt be a big part of season three.


The diplomats United Nations assistant undersecretary Chrisjen Avasarala (Shohreh Aghdashloo) is as delightfully foul-mouthed as she is fabulously dressed. A master manipulator, she’s also the queen of the withering put-down, and she’s spent her entire career advocating on behalf of her beloved Earth. But as whip-smart as Chrisjen is, she underestimated the evil cunning of her boss at the UN, Sadavir Errinwright (Shawn Doyle), who was secretly working with Jules-Pierre Mao behind her back. After coming clean to Chrisjen about his misdeeds, and seemingly agreeing to fall on the sword for the Eros near-disaster, Errinwright murders his Martian counterpart (making it look like a heart attack), wrests control of the protomolecule project from Mao, and puts Chrisjen in his crosshairs. As season three will no doubt demonstrate, the time for polite meetings is way past over for these two former colleagues.

The Martian When we first meet Bobbie Draper (Frankie Adams) at the start of season two, she’s a tough, impulsive, totally gung-ho Martian marine, eager to put her training to use and put the smackdown on Earth. But she grows disillusioned after the Ganymede attack when she—the only surviving eyewitness—is forced by her superiors to lie about what happened, including, ahem, that part about the protomolecule-human hybrid she glimpsed ripping people apart on the battlefield. With nothing left for her on Mars, she defects to Earth and becomes part of Chrisjen’s posse, saving her neck when an outer-space meeting with Jules-Pierre Mao goes sideways after Errinwright’s betrayal.


The OPA leaders Fred Johnson (Chad L. Coleman) and Anderson Dawes (Jared Harris) are both OPA bigwigs, so they both believe above all else that the Belt comes first. But they’re pretty much unalike in every other way. Johnson was born on Earth and was a colonel in the United Nations Marine Corps (Earth’s military), but became a scapegoat (and then a pariah) after Earth wiped out a mining colony of rebellious Belters on his watch. Dawes, a born and raised Belter, recruited Johnson into the OPA, where the latter eventually rose through the ranks to control Tycho Station. Their relationship has grown unsteady over the years, thanks to Dawes’ increasingly radical tactics, which bump up against Johnson’s goal that the OPA should be given a seat at the diplomatic table on equal footing with Earth and Mars. But everything between them fractures forever over (what else?) the protomolecule, after Dawes kidnaps a Protogen scientist from Tycho Station, intending to use the man’s knowledge to bring the weapon to the Belt. Little does he know that Johnson has his own protomolecule stash, thanks to Roci engineer Naomi—a Belter who figured that if Earth and Mars both had their hands on it, the Belt should have it, too. Will the protomolecule inspire the two men to work together, and maybe even unite all of the various Belt factions into a united cause? Maybe??


Who (and what) will be new

So far, two new characters are known to be joining the main cast: Rev. Dr. Anna Volovodov (Elizabeth Mitchell) and Klaes Ashford (David Strathairn). In the books—with a storyline that will inevitably be somewhat altered to fit the TV show—Anna is an Earth-born Methodist minister living in a small colony on Europa who’s drawn into the investigation of “the Ring,” the alien gateway that forms as a result of the protomolecule’s activities on Venus. The Ring will likely be a huge part of season three, and (in the books, anyway) Ashford is also a key player in the storyline; he’s the Belter captain of the Behemoth—a battleship constructed by the OPA from the Mormon colony ship Nauvoo, which was commandeered by Fred Johnson in season two as part of the plan to destroy Eros. Beyond reading the novel series, however, the best glimpse of season three comes from the full-length trailer (as well as this very fun Syfy promo video), which suggests that Bobbie and Chrisjen will have some more buddy-team adventures (yes!), the Roci crew will butt heads (of course), Chrisjen will finally meet James Holden face to face, Prax’s daughter still appears to be 100 percent human, the protomolecule is still out there doing terrible things, and Chrisjen will reclaim her authority eventually, delivering a speech that promises—perhaps after the discovery of the alien stargate?—that “we will face the unknown together.”

Why you should watch

We’ve drooled over the characters and story above, but it’s still worth emphasizing yet again how nuanced and layered the writing on The Expanse really is. There’s also a ton of sly humor—mostly due to Chrisjen’s colorful way with language, as well as the excellent chemistry between the Roci mates—and genuinely emotional moments that the show really spends its time building toward, so that the eventual payoff is always earned. Plus, the show is great-looking and technically outstanding—its thrilling special effects (so many awesome, perilous space battles!) and perfectly-calibrated production design (from the sleek interior of the Roci, to Chrisjen’s impeccable accessories, to the eerie blue of the protomolecule) make The Expanse one of the most dazzling examples of scifi worldbuilding that television has ever seen. And, it goes without saying, it’s entertaining as hell. Get yourself some lasagne—the Roci crew meal of choice—and dig in, kopeng!


The Expanse season three premieres tonight on Syfy.