Six years ago, James S.A. Corey, the pen name for Ty Franck and Daniel Abraham, launched their The Expanse series with Leviathan Wakes, spinning out the story of a solar system rife with political divisions, an interplanetary conspiracy, and the crew of a space ship called the Rocinante. In the years since, the story has stretched into multiple installments and a major television series. Last year, Abraham and Franck told The Verge that the last three books would be “one big plot arc coming to the finale.” Persepolis Rising, the first of that trilogy, lives up to that promise and sets the stage for a huge confrontation to finish off the series.

Some spoilers ahead for the first six entries in The Expanse series.

So far, the series has told an overarching story broken roughly into trilogies. Leviathan Wakes, Caliban’s War, and Abbadon’s Gate dealt with the discovery of an alien life form called the protomolecule, which opened an interstellar portal to thousands of other planets. The second trilogy — Cibola Burn, Nemesis Games, and Babylon’s Ashes — dealt with the fallout. Humans could now spread into the galaxy, but at considerable cost to the political order at home. Radicalized groups of Belters, the disadvantaged citizens of the outer planets and asteroid belts, waged an apocalyptic war against Earth and Mars, bombarding humanity’s home planet with asteroids.

Babylon’s Ashes wrapped up many of the existing threads from those two trilogies well enough that it could have satisfyingly concluded the series, which puts Persepolis Rising in an interesting place. There are still stories to explore, but after six books, Abraham and Franck also face the challenge of creating something that’s more than a routine adventure. So with the first three words of the book, they propel the story three decades forward. While there’s a huge amount of backstory in those first six books, this 30 year jump feels as though it’s a bit of a reset for newcomers. While I would recommend reading the rest of the series, Persepolis Rising covers its most important plot points.

At the start of Persepolis Rising, the solar system has found an equilibrium. The OPA, Belter’s dominant political faction, has transformed into the legitimate Transportation Union, which helps supply 1,300 human-colonized planets across the galaxy. Earth and Mars have put aside their adversarial relationship to form the Earth-Mars Coalition, and protagonist James Holden and the crew of the Rocinante are still doing the odd jobs required of them.

But there’s another danger lurking: a brutal, technologically advanced empire called Laconia, formed by a group of Martians who abandoned the solar system in an earlier book. Laconia has thrived in the three decades hence, under the leadership of the immortal High Counsel Duarte. Now, Duarte has dispatched a fleet back to the gate system and the station that controls it, launching another war for control over the solar system.

The Expanse books have always been bleak, cynical affairs, but this new installment feels especially hopeless. At the beginning, Rocinante captain Jim Holden and his partner Naomi — once iconic figures in the solar system — intend to retire and pass control of the ship to former Martian Marine Bobbie Draper. But the Laconian military comes through the gate and commandeers their station, threatening to destroy entire worlds if its inhabitants resist.

Persepolis Rising is all about the sudden arrival of an authoritarian force that seeks to utterly dominate the status quo for its own purposes. Duarte proves to be a brutal dictator. Dissent is harshly punished, with victims sent to “the pens,” where they’re deliberately infected with the protomolecule for experimental purposes. While the urge to draw parallels to the last year of politics is strong, the setting feels like Paris in 1940, after Nazi forces invaded France. Under Duarte’s orders, a young officer named Captain Santiago Singh brutally cracks down on dissidents on Medina Station, imprisoning, torturing, and killing those who resist Laconian rule.

With the arrival of the Laconians, the crew of the Rocinante quickly jump into the fray, plotting bombings, espionage missions, and eventually, escape. We’re already familiar with the characters of Alex, Amos, Bobbie, Clarissa, Naomi, and Holden, but the new threat challenges them in ways we haven’t seen in the past six books. (We get a good answer to the question, who would win in a fight, Amos or Bobbie.) Abraham and Franck develop Singh as a loyal Laconian officer who believes that he’s helping humanity navigate intergalactic chaos by bringing everyone into a new, efficient era. They also bring back Drummer, the Transportation Union’s leader, who’s facing the Laconian’s seemingly unstoppable threat.

The book does fall short in some places. The Laconians feel too much like a stereotypical evil empire, complete with super weapons and armored foot soldiers. Singh himself feels particularly naïve — it should be obvious why governments don’t want to accept Laconian rule. One would think a powerful military power would have a more realistic understanding of invasion forces and dealing with insurgencies. Even if the series is reaching for new stakes in its final arc, it’s less interesting than the nuanced politics of past books.

But for fans of The Expanse, it’s still a welcome return to an established and familiar world. What makes up for these weaknesses is its momentum. Like the novels that came before it, Persepolis Rising is a tightly-plotted thriller that juggles a variety of often-opposing threads. As the action plays out, it’s clear that Abraham and Franck have a huge finale planned, with huge stakes and challenges ahead for its characters.

Update, December 11, 11:00PM: An early version of this review stated that the character Drummer was introduced in this book. She was introduced earlier in the series.

Photography by Andrew Liptak / The Verge