When it comes to series, much is made about the concept of “middle book slump”: the idea that middle books, lacking the novelty and opening punch of a first volume, or the satisfaction of a conclusion, are inherently prone to being weaker than their companions. Like many “rules” of the genre, it’s one where I can think of more exceptions than straightforward examples, but rarely does a book raise the bar on its predecessor as much as Jade War, by Fonda Lee, the second book in the Green Bone Saga. Jade City was one of my favourite books of 2017, an epic fantasy told through the ups and downs of one powerful family on the island of Kekon as they struggle to maintain their position against their rivals. Jade War does the same, except it does so now on a global stage, bringing to life a secondary world grappling with the sociopolitical impacts of technological change. The stakes are higher, the schemes are more ambitious, and there are still plenty of opportunities for superpowered martial arts and even the occasional car chase. Truly, what more could one ask for?

The family at the heart of the Green Bone Saga is the Kauls, leaders of the No-Peak Clan, one of several “Green Bone” clans who basically operate as politically legitimate gangsters in Kekonese society. No Peak has emerged intact from open conflict with the rival Mountain Clan and their ambitious leader Ayt Madashi, but this victory hasn’t come without losses. Kaul Lan, the eldest member of No Peak’s current ruling generation and “Pillar” (leader) of the Clan, has been killed, leaving his hotheaded, violence-prone younger brother, Hilo, in charge. Meanwhile, Kekon is being increasingly drawn into the global politics surrounding the war brewing on the neighbouring continent: a proxy war between two larger powers which looks likely to be won or lost based on a resource that only Kekon can provide.

If you’ve paid attention to the book’s title, you will not be surprised to learn that this resource is jade. Specifically, Kekon is the source of a unique, bioreactive jade which grants its wearer various supernatural abilities, most of which amount to making them better at punching one other (although there are some exceptions to this, such as Perception, which allows the wearer to sense how nervous the other person is just before they punch them). Unfortunately for all the would-be superpunchers out there, wearing jade is both dangerous and addictive, and for all but a subset of one Kekonese ethnic group, exposure quickly results in a disease known as “the Itches,” which is exactly as nasty as it sounds. That means that, until recently, bioreactive jade has been of little international interest, but all that has changed with the creation of Shine, a new drug which enables anyone to use it. For Kekonese society, Shine represents a threat to the established order of those clans which, until now, have had the monopoly on the use of jade. To the rest of the world, it represents an opportunity, both for militaries and for the criminal networks smuggling it out worldwide. For the Kauls, the pressing challenge is to navigate the risks and opportunities presented by this international demand, and their own position in this new world order—all while avoiding the machinations of Ayt Madashi, who is still trying to bring down No Peak.

The way jade shapes the world around it is the most impressive facet of worldbuilding here, introducing a unique magic system with rules and limitations which affects the entire structure of society in Kekon, its relationships with other nations, and its diaspora communities. For all the martial awesomeness on display—Lee certainly knows how to write an awesome fight scene, and I say that as a non-visual reader on whom cinematic action sequences are often wasted—Jade War makes it clear that the mineral’s greatest power is the social and economic clout it gives its wielder. Jade wielders on Kekon are supposedly governed by a cultural code known as Aisho, and by the structures imposed by their clans, as well as an intricate set of norms (many of which are super-patriarchal) that govern how they act, talk, and conduct themselves in wider society. Even those scenes which deal explicitly with the biological properties of jade—be they big duelling set pieces, unpleasant illustrations of jade overexposure, or games designed to slowly and safely expose children to the substance—are contextualised within the wider cultural significance of this substance that sits at the centre of Kekon’s identity. The inclusion of the Kekonese diaspora in its multiple forms, including “Barakan” immigrants in neighbouring countries as well as the more far-flung community of Kekonese-Espenians, adds further nuance, as the use and significance of jade in these cultures rubs up against norms in Kekon and vice versa.

At the heart of Jade War’s complex, multi-stranded narrative are the Kaul siblings: Clan Pillar Kaul Hilo, his sister Kaul Shae, and their adopted younger brother Emery Anden. Each, to some extent, finds themselves well out of their comfort zone by the opening chapters of Jade War. For Hilo, taking on leadership means detaching himself from the clan’s military side. Shae, whose arc in Jade City involved reconnecting with her Green Bone identity after leaving Kekon for Espenia before the events of the book, has now taken on the position of “Weather Man,” in charge of its trade relations both at home and abroad. Shae now walks a tightrope between using her international experience to the clan’s advantage while upholding her reputation as a loyal member of the Clan, which would be damaged if she comes across as too aligned with foreign interests. For Anden, the events of Jade City have forever changed his relationship with jade; with few options remaining, his family send him to Espenia where he becomes the reader’s window on the Kekonese diaspora community there.

Also prominent is Maik Wen, Hilo’s wife and a “stone-eye,” born to a jade-wearing family but completely non-responsive to jade, as she seeks to develop her own role within the clan. For both Wen and Shae—and, indeed, for Ayt Madashi of the Mountain clan—their experience with power is highly shaped by being women in a society which is theoretically moving towards a more egalitarian view of gender but is, in reality, nowhere near obtaining it. It’s intriguing to see the strands of patriarchy and its different manifestations across Kekon and Espenia, from Wen’s use of female-only spaces to build a spy network beneath the notice of clan leadership, to Shae’s meetings with Espenian generals who keep addressing her male second, to Anden failing to notice that all the power in his informal Espenian Clan is concentrated in the hands of men. The manifestations of male power are just one area where the cultural nuances in Jade War shine. Each of the book’s characters could easily have an essay written about them, but the common thread is that each seems completely embedded within the cultural pressures that created them. From the Kauls and their associates, to the glimpses we see of those beyond their immediate network, to even more occasional perspectives from non-Kekonese characters, everyone in Jade War feels utterly convincing as three-dimensional people in a living, breathing world.

That nuance is important, because it grounds all of the intricate decision-making and machinations of the book—nearly six hundred pages of it—in motivations that remain believable to the characters and easy to track even as the book skips across both continents and years. The sense of time passing in Jade War is subtle, signalled through young children growing up or characters popping up years apart in new situations and positions rather than by really calling attention to the fact that this is a narrative spanning a significant chunk of its characters’ lives; the people themselves change, but they don’t change that much, and even for those growing into new roles, there are basic motivations that never remain far from the surface. Nowhere is this more evident than with Hilo, who remains, to put it bluntly, a total disaster. While Hilo’s status as Pillar is generally stable (and the book goes out of its way to note how his leadership style is still effective in keeping No Peak running while being very different to his brother’s in how it relies on charisma and personal connections), he also has a hand in some of Jade War’s most brutal scenes, including the murder of a family member and a creatively awful execution. In other situations, the juxtaposition between Hilo’s jovial family scenes or his steadying words to a promising young Green Bone, and his active participation in the Clan’s most violent acts, would be impossible to reconcile in a single character. But because Jade War is so careful and intricate in how it sets out the Green Bone Culture, and the values Hilo specifically has chosen to take out of it, the contrast isn’t a contradiction at all. All of Hilo’s actions are motivated by an ethical code which inextricably links his Clan and family and puts them at the heart of every decision he takes; the execution of a criminal who may have desecrated his late brother’s memory furthers that just as much as does bringing up one’s children in a caring, jade-filled home. The thread which runs through Jade War about Hilo’s relationship with his children (including his adopted nephew), and the way he introduces them to his clan work, is one of the best plotted and most gut-wrenching through-lines of the book. It all adds up to one of the most satisfyingly detestable “protagonists” I’ve encountered in fiction.

Of course, even in six hundred pages there’s not space for every single corner of this world to have equal attention, and despite the global scale, the other countries of this world are very much seen through a Kekonese lens. Espenia, for example, offers a rather ahistorical vision of a “western” country: there’s no space given to past colonial escapades or other factors which would justify its capital, Port Massey, being a sort of London-slash-New-York melting pot stand-in. While there are characters who question the broader underpinnings of Kekonese society, there’s not much space given to speculative alternatives for Kekon’s domestic politics, which relies on a “separation of jade and state” that seems to have barely been true in practice and is being even more threatened by the current Clan War. And despite playing out on a global scale, the focus on the fate of the No Peak Clan ultimately means Jade War doesn’t have much to say about whether there might be alternatives to the neoliberal world order its characters are reacting to. Technologically, Jade War’s world seems to be somewhere around the mid to late twentieth-century (air travel and international phone calls are commonplace, at least for people with the Kauls’ status, but there’s no internet); its political dilemmas also feel very embedded in that time. While that doesn’t make the speculative aspects of it feel less relevant to the current genre conversation, it did leave me with more questions about the assumptions this world is built upon and what a “good ending” for the Kauls might look like on a wider scale.

All in all, Jade War is an outstanding example of a sequel building on the foundation laid by its first volume and spinning it into something even more satisfying and intricate. Jade War’s story is multi-layered and satisfying, its characters rooted in a nuanced system of values which makes their actions in turn relatable, intriguing, and occasionally abhorrent without ever feeling out of place. Jade War finishes on much the same note as Jade City, bringing its core threads to a close even as the characters themselves find themselves uncertain or facing changes to what the future holds. The final volume of the trilogy, Jade Legacy, is expected later this year, and I’m highly invested in finding out what’s in store for Shae, Anden, Wen, and (ugh) Hilo as their story draws to a close. As it stands, Jade War is going to be a hard act to follow.