A Fire Upon The Deep - Plot

Plot

The novel posits that space around the Milky Way is divided into concentric layers called Zones, each being constrained by different laws of physics and each allowing for different degrees of biological and technological advancement. The innermost, the "Unthinking Depths", surrounds the galactic core and is incapable of supporting advanced life forms at all. The next layer, the "Slow Zone", is roughly equivalent to the real world in behavior and potential. Further out, the zone named the "Beyond" can support futuristic technologies such as AI and FTL travel. The outermost zone, the "Transcend", contains most of the galactic halo and is populated by incomprehensibly vast and powerful posthuman entities.

A human expedition investigates a five-billion-year-old data archive that offers the possibility of unimaginable riches for the ambitious young civilization of the Straumli Realm. The expedition's facility, called High Lab, is gradually compromised by a dormant super-intelligent entity (actually encoded within the archive) later known as the Blight. The Blight rapidly learns how to infiltrate and control the computer systems of High Lab, and even develops the ability to possess and control the living humans. The novel starts with an imaginative description of the evolution of this superintelligence through exponentially accelerating developmental stages, culminating in a transcendent, nigh-omnipotent power that is unfathomable to mere humans. Shortly before its final "flowering", the changes in a single minute of the Blight's life are said to exceed those of 10,000 years of human civilization.

Recognizing the danger of what they have awakened, the researchers at High Lab attempt to flee in two ships. Suspicious, the Blight discovers that one of the ships contains a data storage device in its cargo manifest; assuming it contains information that could harm it, the Blight destroys the ship. The second ship is allowed to escape, unharmed, as the Blight assumes that it is no threat; but later realizes that it actually held a countermeasure, one of the few things in the universe that the Blight fears.

The ship lands on a distant planet with a medieval-level civilization of dog-like creatures dubbed "Tines", who live in packs as group minds. The ship is revealed to be a sleeper ship, carrying most of High Lab's children in "coldsleep boxes". The boxes are rapidly failing and the surviving adults begin unloading them, but are killed when one of two rival forces of Tines seize the ship. The faction that initially contacts the humans, led by a Tine known as Steel, kills the adults and destroys many of the coldsleep boxes. They also capture a boy named Jefri Olsndot, whom Steel intended on killing but eventually exploits in order to develop advanced technology (such as cannon and radio communication). Jefri's older sister, Johanna, is rescued by Pilgrim and Scriber, wandering Tines who bring her to the rival faction, led by Woodcarver. She is asked to help develop technology that could gain the upper hand in the impending war.

A distress signal from the sleeper ship eventually reaches "Relay", a major node in the galactic communications network. A benign transcendent entity (known as a "Power") named "Old One" contacts Relay, seeking information about the Blight and the humans who released it. Old One constructs a seemingly human man, Pham Nuwen, to act as its agent. Pham and Ravna Bergsndot – a human employee of Relay's owners, the wealthy Vrinimi Organization – trace the sleeper ship's signal to the Tines world. Old One designs a vessel, the Out of Band II, to reach the Tines world and to investigate what the ship carried with it from the High Lab.

The Blight attacks Relay and Old One. Old One has given Pham the information necessary to activate the Blight Countermeasure subconsciously, a process known as godshatter (which will result in his death). Pham and Ravna escape Relay's destruction in the Out of Band II. After arriving at the Tines homeworld and allying with Woodcarver to defeat Steel, Pham initiates the Countermeasure, which extends the Slow Zone by thousands of light-years to enclose the Blight. This ends the threat of the Blight at the cost of wrecking thousands of uninvolved civilizations, causing trillions of deaths and potentially the extinction of several galactic races. The process strands the other humans on the Tines world, now in the depths of the "Slow Zone" where rescue by an advanced civilization is impossible.