The term Xenocide is a science fiction neologism that means an act of genocide directed towards an alien species.

The cover art for Xenocide is similar to that of Speaker for the Dead.

Xenocide is the third novel in the Ender's Game series of books by Orson Scott Card.

Storyline

Following the events of Speaker for the Dead, we find Ender a member of a human colony on the planet Lusitania, unique in human space in being inhabited by two other sentient species: the Pequeninos, and the Hive (transplanted to this world by Ender in part penance for his near-total destruction of their species in Ender's Game).

Unfortunately, the Lusitanian ecosystem is pervaded by a virus, named 'descolada' by the Humans, so adaptable as to be potentially fatal to all living things. The native pequininos are adapted to it (and in fact attained sentience partly through the great rearrangements of their genome that the virus triggered), Humans can survive in its presence through continuing medical intervention via dietary supplements, and the Hive have their own mechanisms to deal with it.

Nevertheless, were any carrier of the virus to set foot upon an uninfected world, an ecological catastrophe would ensue, wiping out all but a handful of species. The threat presented by this pathogen is great enough to frighten the Human government off-planet, the Starways Congress, into secretly dispatching a fleet of ships armed with the Molecular Disrupter Device (M.D. Device) that can shatter planets, to destroy Lusitania.

In contact with an artificial sentience created by the ansible network by which spaceships and planets communicate in realtime across galactic distances, Ender and the Lusitanians are made aware of the threat. The sentience, named Jane, will not permit the destruction of Lusitania until the inhabitants have found an interstellar means of escape; to delay its attack, she shuts down the ansible connection to the fleet, even though this may lead to her discovery and termination.

The Lusitanian situation is placed before the superhumanly-intelligent leaders of the world named Path by the Starways Congress, the interstellar governing body. On Path, a cultural planetary enclave modelled on early China, a culture has been fostered centered around the godspoken, those who hear the voices of the gods through the acts they carry out compulsively. It later becomes clear that the godspoken of Path are victims of a cruel government project, unknowingly granted great intelligence by genetic modification as a resource to be exploited, but - out of fear that their superior intellect might enable them to seize power - also inflicted with a crippling obessive-compulsive disorder linked to the intelligence trait. The siting of this experiment in a culture bound by four dictates - obey the gods, honor the ancestors, love the people, and serve the rulers - is a further safeguard against rebellion. The current leader of path is Han Fei-Tzu, forced by his OCD to dance; his daughter and potential successor, Han Qing-jao, must periodically trace lines on the floor with her eye, sometimes for hours at a time. Qing-jao is given the task of discovering why the Lusitania fleet has fallen silent as a test for her coming-of-age.

Jane senses that Qing-jao is the one who will eventually discover her and reveal her presence to the Starways Congress. Since the Congress will not abide a non-Human sentience in control of the ansible network that binds their galaxy, they will shut down the network, killing Jane. Jane does her best to subtly frustrate Qing-jao, but she knows that it's merely a matter of time.

Meanwhile, Qing-jao stumbles across the existence of Jane by tracing the identity of Demosthenes, the pen name of an essayist who has revealed and been arguing against the planned destruction of Lusitania. Discovering that Demosthenes must be Valentine Wiggin, Ender's sister, but that Valentine has been on a starship for the last thirty years (relative to Path's time; on the ship, only a few weeks have passed) Qing-Jao infers that a sentient computer program closely tied to the ansible network must be responsible for hiding Demosthenes and publishing her work whilst she is in transit.

About to be discovered, Jane reveals herself to both Han Fei-tzu and Qing-jao, telling them about the manipulation they and their world has been subjected to and begging forbearance on their report to the Starways Congress. Han Fei-tzu, already harbouring suspicions about their condition, accepts the news, but Qing-jao cannot, clinging to her traditional religious interpretation of the godpeaking compulsions she suffers. Feeling betrayed by her father, Qing-Jao reports the presence of Jane to Congress, which institutes the complex and slow process of arranging a simultaenious shutdown of all ansibles across multiple worlds, which would result in Jane's destruction.

Regretting his daughters act, Han Fei-tzu assists Jane and Ela, biologist back on Lusitania and Ender's adopted daughter, in designing a counter-virus to the descolada. Unfortunately, this construct, derived from the descolada and nicknamed the recolada, although theoretically stable once created, destroys itself during any attempt to synthesise it by conventional means through the descolada's own complex mechanisms of self-preservation.

All seems lost until Jane proposes a solution derived from her machine-speed mind and access to the totality of human knowledge. She can design a device which could carry passengers outside of the Universe into a pseudospace within which acts of will can be physically manifested. Ela could project her detailed understanding of the recolada into creating the stable form of the counter-virus there, and it could then be returned to Lusitania.

This experiment is undertaken successfully, although the passengers of the device bring back more than planned, as Ender in particular carried a heartfelt wish with him that was made flesh on his return - the company of his sister and brother of the age he knew them best.

With a cure to the descolada to hand and growing public pressure against a second xenocide on Lusitania, the future of the three sentient races on the planet seems more secure. Jane and Miro use the device to create a cure for the OCD component of the intelligence trait on Path, and travel there to present it.

Qing-Jao, relieved of the biological origins of her compulsions, continues to act them out as the last remant of the old ways of her world.