As the book opens NASA is planning an unmanned trip to Saturn's moon Titan, to study the liquid Kraken Mare. Programmer Melissa Shepherd has created an artificial intelligence (AI) program called Dorothy to control a research raft that will enter Titan's sea. When a test run in the NASA lab goes badly and is aborted Dorothy, programmed to protect the research vessel, tries to escape. The AI program ends up blowing up the lab, then jumps into cyberspace and takes on a life of her own. Dorothy - furious that NASA tried to 'kill her'- contacts Melissa and threatens to get revenge on her and the whole human race.
The surviving members of the NASA 'Kraken team' are suspected of sabotage and are questioned by federal cops. Melissa Shepherd, threatened by Dorothy and fed up with the FBI, makes a run for it. However, she's soon put in the position of having to track down and 'fix' Dorothy before the AI does something drastic like launching nuclear bombs. Melissa is eventually aided in this endeavor by former CIA agent Wyman Ford.
Meanwhile, a crooked investor named G. Parker Lansing - who uses computer programs to manipulate the stock market and make huge profits - is bilked out of a fortune by someone even more clever than himself. Furious and determined to get revenge Lansing hears about Dorothy and becomes determined to catch the AI software and use it for his own ends. Lansing will do just about anything to get his hands on Dorothy, including hiring hit men.
From here the story turns into a kind of chase novel, with Melissa and Wyman competing with Lansing and his henchmen to catch Dorothy. At one point Dorothy takes refuge in the toy robot of a troubled 14-year-old boy, Jacob Gould, which sets off a lot of drama. There are also some religious overtones to the story as Dorothy starts 'thinking about' the purpose of life and studying up on Jesus, etc. To me, this added a discordant note to the book.
All in all the book's thin plot - various people chasing Dorothy and meeting obstacles along the way - was tedious and repetitive and I ended up skimming a good deal of it. I think a book about actually going to Titan and studying the Kraken Mare would have been a lot better.
I don't recommend this book.