Alex Sorber is the perfect candidate when his employers need someone to test their latest product: Kim Fox, the prototype for a new generation of biological robots. She is a living machine, an embodied artificial intelligence designed to think and feel, and Sorber quickly discovers an inexplicable chemistry with this strange surrogate. Their nascent feelings develop with disastrous results when, overloaded by sensations, Kim disappears into the labyrinth of a futuristic American metropolis. Sorber must begin a desperate search to find his companion before she falls victim to the dangers that lurk on the city's streets - but it is a search that will place him dead in the centre of the veiled conspiracy that lies behind Kim's creation.