The Expanse Season 4 Review – A New World, A Wider War

Introduction: The Expanse Reborn on a New Frontier

The fourth season of The Expanse arrived carrying the weight of extraordinary expectations. Rescued from cancellation by a passionate fan campaign that famously caught the attention of Jeff Bezos, its debut on Amazon Prime Video was not just another premiere; it was a vindication. The season had to prove that the fan fervor was justified and that the series had more stories worth telling. The verdict is unequivocal: Season 4 not only meets the high bar set by its predecessors but elevates the entire project. By masterfully balancing a contained, high-stakes planetary conflict with the escalating political tensions across the entire solar system, the season cements the show's status as one of the best and most intelligent science fiction series on television. This new chapter proved that with a new home and a bigger canvas, The Expanse was ready to explore its most ambitious frontiers yet, beginning with humanity's first tentative steps onto an alien world.

For a full overview of the show's legacy, check out our The Expanse TV Series Guide.

The Expanse: Season 4 [Blu-Ray]

The Roci lands. A new world awaits. Own the stunning first Amazon season.

1. Welcome to Ilus: A Space Western at the Edge of Known Space

The central narrative of Season 4 transports viewers beyond the Ring Gate to Ilus (also designated New Terra), an Earth-like world that represents both humanity's greatest hope and its most profound new threat. This storyline, drawing heavily from its source novel's western influences, serves as the crucible for humanity's extrasolar ambitions. It blends the classic tropes of a frontier western—disputed claims between desperate refugees and a powerful corporation with an official charter—with the hard science fiction that defines the series. On Ilus, the familiar conflicts of ideology and survival are recast under an alien sky, creating a tense, claustrophobic drama that tests the limits of every character involved.

1.1 The Core Conflict: Settlers vs. Corporation

At the heart of the Ilus storyline is a classic and explosive conflict between a group of Belter refugees from Ganymede and the corporate security force of Royal Charter Energy (RCE). The crew of the Rocinante is dispatched by the UN to mediate, only to find themselves caught between two intractable positions.

• Competing Claims: The Belters, having fled the destruction of their home, were the first to pass through the Ring and settle on Ilus, claiming it as their own. However, the UN granted an official charter to RCE to survey and exploit the planet's resources, setting the stage for a legal and physical confrontation over ownership.
• Clash of Ideologies: The conflict is fueled by fundamentally different worldviews. For the Belters, Ilus is a last chance—a promised land to call home after a lifetime of marginalization. For RCE and its hardened chief of security, Adolphus Murtry, the planet is a corporate asset and the Belters are illegal squatters. Their mandate is driven by profit and contractual obligation, not pioneering spirit.
• The Rocinante's Role: James Holden and his crew are tasked with the near-impossible mission of preventing bloodshed. They must navigate the legitimate grievances of the Belters and the legal authority of RCE, a task made infinitely more difficult by the deep-seated mistrust and escalating violence from both sides.

1.2 The Alien Threat: When a Planet Fights Back

As the human factions square off, Ilus itself becomes an active and terrifying antagonist. The dormant, protomolecule-based technology left behind by the Ring Builders begins to reawaken, turning the seemingly idyllic world into a death trap. Ancient, poorly understood alien machinery, a hostile planetary environment, and catastrophic planetary events force the rival humans into an uneasy and desperate struggle for mutual survival. This escalation reaches its apex when an alien reactor explodes, triggering an extinction-level event that threatens to wipe out everyone on the planet, forcing a temporary and fragile alliance against a force beyond their comprehension.

1.3 A New Kind of Villain: The Pragmatism of Adolphus Murtry

The Ilus conflict is personified by its primary antagonist, Adolphus Murtry, brought to life with chilling intensity by actor Burn Gorman. Murtry is a departure from the series' previous villains. He is not a megalomaniac or a political schemer operating on a grand scale; he is a man with a job to do, and he will do it with brutal, unwavering pragmatism. His commitment to his corporate mission is absolute, and he views any opposition not as a moral challenge but as an obstacle to be removed, violently if necessary. This grounded, focused antagonism makes him a uniquely compelling and frightening foe, representing the human capacity for ruthlessness in the service of ordinary, tangible goals.

2. Beyond the Ring: Expanding the Political Narrative

In a significant and brilliant departure from the source novel, Cibola Burn, the showrunners made the strategic decision to expand the narrative beyond the confines of Ilus. While the book focuses almost exclusively on the planetary conflict, leaving major political figures like Chrisjen Avasarala largely absent, the series interweaves this with crucial subplots on Earth and Mars. This choice was vital, preventing the story from feeling isolated and maintaining the grand, system-wide political scope that is a hallmark of the series.

2.1 Earth: The Perils of Power

On Earth, Secretary-General Chrisjen Avasarala finds her authority challenged by a popular and ambitious new rival, Nancy Gao. This political storyline masterfully explores the immense difficulty of governing in a new era where thousands of habitable worlds are suddenly within reach. Avasarala's hardline, pragmatic decisions, once seen as necessary for survival, are now political liabilities in a more hopeful age. Her struggle to maintain power highlights the shifting political landscape and the personal cost of leadership when the old rules no longer apply.

2.2 Mars: A Dying Dream

Meanwhile, Bobbie Draper's arc on a post-Ring Mars provides a grim look at a society in decline. With the terraforming project—the single, unifying dream of Martian society for generations—now rendered largely obsolete by the existence of pre-made habitable worlds, Mars faces an existential crisis. Bobbie’s entanglement with corrupt police and criminal enterprises smuggling Martian military hardware effectively illustrates the planet's societal and economic decay. This subplot is critically important for the overarching narrative, laying the foundation for the rogue Martian conspiracy led by Admiral Winston Duarte. His faction trades advanced Martian military hardware to Marco Inaros' Free Navy in exchange for the last active protomolecule sample, which they require to activate alien technology in the distant Laconia system.

3. The Art of Adaptation: From Cibola Burn to Season 4

Season 4 stands as a masterclass in literary adaptation. While the core plot on Ilus is drawn faithfully from the fourth novel, Cibola Burn, the series makes several significant structural changes that immeasurably benefit the story in a visual medium. That these changes feel so intelligent and true to the spirit of the source is no accident; the book authors, operating under the pen name James S.A. Corey, are directly involved as producers and writers, guiding the evolution of their world for the screen.

By breaking away from the singular focus of the novel, the showrunners achieved several key objectives. Including the Earth and Mars subplots prevents the main Rocinante crew from feeling isolated from the larger universe for an entire season while effectively laying the groundwork for the explosive conflict of Season 5. This is exemplified by small but significant plot alterations, such as the fate of Adolphus Murtry. In the novel, he survives Ilus and is taken into custody, spending months imprisoned on the Rocinante. In the show, he is killed by Amos in a decisive confrontation—a change that provides a more definitive, dramatic conclusion for the season's villain while sharpening Amos's character arc.

4. The Human Element: Pitch-Perfect Casting and Performance

A core and consistent strength of The Expanse is its ensemble cast, whose members embody their characters with a depth and nuance that feels consistently authentic. This quality is on full display in Season 4, where both veteran and new actors deliver performances that ground the epic science fiction in relatable human drama.

• The Core Crew: The actors portraying the Rocinante crew—Steven Strait (Holden), Dominique Tipper (Naomi), Wes Chatham (Amos), and Cas Anvar (Alex)—continue to excel. In Season 4, they skillfully portray the immense strain of their new mission on Ilus, showing how the pressures of this alien world test their loyalties and force their relationships to evolve in compelling ways.
• Compelling Newcomers: The season introduces several new characters, and the casting remains impeccable. Burn Gorman's intense, coiled performance as the ruthless Adolphus Murtry is a particular standout, creating a villain who is both despicable and utterly believable in his convictions.
• Character Embodiment: There is a well-deserved sentiment that the series has found the perfect actors for these characters. This is not just a platitude; it is proven by their dedication. Wes Chatham, who plays Amos Burton, demonstrates such a profound connection to his character that he is now co-writing an official, in-canon comic series, The Expanse: A Little Death, that continues Amos's story beyond the show. It is a powerful testament to how deeply the cast inhabits this world.

Cibola Burn (Book 4)

The book that inspired the season. Read the original space western story.

5. Conclusion: A Fantastic New Chapter and a Solid 9/10

Season 4 of The Expanse is a triumphant success. It is a fantastic new chapter that not only justifies the series' rescue but demonstrates its boundless potential. The season skillfully adapts its source material, making intelligent changes that enhance the narrative for television while expanding the universe in compelling and necessary ways. Supported by perfect casting, intricate plotting, and an unwavering commitment to intelligent, character-driven science fiction, it delivers on every level. As praised by astrophysicist Katie Mack, the show’s dedication to real physics—using thrust gravity, the Coriolis effect, and the realities of vacuum exposure not as background details but as crucial dramatic tools—sets it apart. With this season, The Expanse not only satisfied its loyal fanbase but proved that it has even greater, more ambitious stories to tell, solidifying its place as one of the best science fiction shows ever made.

📌 FAQ