On Gullstruck Island there are three volcanoes: King of Fans, his wife Lady Sorrow, and his rival Lord Spearhead. Once, Lord Spearhead courted Lady Sorrow and King of Fans raged down the valley. Once, Lord Spearhead lost his temper and rocks fell on the world. The indigenous Lace knew this, and when the Cavalcaste invaders settled in the valleys they stole people away and sacrificed them to the volcanoes in order to preserve the peace. The price they paid was a mighty vengeance against them. Their priests and temples were destroyed and they were driven to the edge of the island. Their once proud position as negotiators between the other indigenous peoples collapsed. Their permanent smiles, once a symbol of their go-between role, have become a sign that they are untrustworthy.

But all is not well on the island. As the Lace eke out a living at the margins, the Cavalcaste are being pushed from the centre of the island by their own dead—the Cavalcaste funeral practices demand that the dead be housed in urns and given land and possessions of their own. Cavalcaste settlements are expanding doughnuts. The best land is now forbidden.

In a small village on the coast, Hathin lives with her sister, the Lady Arilou. Arilou may be a Lost, a person whose spirit and senses travel from their body, who can observe the whole island in their travels. But Arilou has never spoken and the village is engaged in an conspiracy to preserve the status that goes with the belief that there is a Lost in the village. Hathin, younger sister, has been groomed to serve the conspiracy. When a Lost councillor arrives to test Arilou, there is consternation. When the councillor dies in the middle of the test, the village, terrified of persecution, covers up his death. It is a disastrous decision. When the Lost councillor's companion is found half dead, the villagers find themselves accused of murder. The entire village is wiped out and a pogrom against the Lace spreads across the island. Only Hathin and Arilou survive and Hathin, taking the butterfly mark of Revenge, heads for the jungles to join the Lace Reckoning, a band of cameroons hiding out and engaged in low level guerrilla warfare against the Cavalcaste. As she travels, she discovers that all the Lost except Arilou have died in their sleep. Only Arilou is left, and she has become both precious and threatening to someone. Yet Arilou, to all intents and purposes, is an imbecile.

Nothing is quite what it seems, however. As the tale continues it becomes clear that the Lace have not earned their destruction: their decision might have been a catalyst, but the genocide that is unleashed proves to be well planned and connected to the deaths of the Lost.

Gullstruck Island is not as well written as either of Hardinge's books. The sentences are often clumsy, and there is little of the delicate witticism of either Fly By Night or Verdigiris Deep. But this is perhaps appropriate. Gullstruck Island is a tale of axes and bludgeons, not rapiers. Hardinge's tale of many peoples on one island is as far from the classic secondary world fantasy religion of distinct groups of people as it is possible to get. Although the notes at the back refer us to a trip to New Zealand, I was strongly reminded of what I have read and heard of Jamaica. The peoples of Gullstruck Island are never as divided by race as those who wish to divide them would like. Almost everyone we meet is of mixed blood. Skin colour varies and cannot be used to easily pigeonhole anyone but the Cavalcaste aristocracy (whose cold northern origins implies they are white). People are identified instead by cultural markers (teeth decorations, or dyed lips) and even more by cultural habit and belief.

The innate delicacy of Hardinge's touch is most evident in this issue of habit and belief. As the book unravels, the position of the Lace as the superstitious shifts in two directions. Many of their superstitions are grounded in fact—a not unusual turn in a post-colonialist fantasy novel—but more to the point, everyone else turns out to be just as superstitious, and many social relations depend on everyone accepting the truth and power of other people's superstitions. Similarly, the odd cultural practices of the Lace—the permanent smile, keeping no death records, names that are natural sounds—gain context, while the habits of the Cavalcaste—building stables in a land with no horses, giving the best land to the dead, issuing edics about the trapping of beavers—begin to demonstrate to everyone the complete irrelevance to everyday life of the Cavalcaste government. By the end of the book, it is clear that Cavalcaste has lost its power; it was just that no one had really noticed.

Gullstruck Island contains the classic YA motif of the protagonist learning to know herself, but the book can also be understood as entire peoples coming once again to know themselves and to know their lands. What begins as one of the simpler of Hardinge's books grows in subtlety and complexity as the ground of the book grumbles and shifts and slides under our feet with the movement of the mountains. When the world does come crashing down, like lava, it leaves behind it fertile soil.

Farah Mendlesohn is the author of Rhetorics of Fantasy, and the editor of On Joanna Russ. She edited the journal Foundation for six years.