In a city ruled by the multinational corporations, identity is crucial; no one can get anywhere without being monitored, logged, and status-checked. Fortunately for some, if a new I.D. is needed, there are "simmers," backstreet I.D. thieves that can create new personas by stealing the identities of others. Libra Kelly is a simmer with an axe to grind, doing jobs that cause trouble for the corporations free of charge, but soon finds herself stuck with a terminally diseased I.D. and a price on her head!