Cath and Bruce live on Freeside where they devote themselves to the art of partying. Case first meets Cath at a bar, and she brings him to meet Bruce. Bruce gives Case his first taste of betaphenethylamine, a drug that can bypass Case's modified, antidrug pancreas. Later, Cath meets Case again at a bar and entices him with another hit of betaphenethylamine and a little one-on-one partying (if you catch our drift), but Case runs out on her.
Cath gets very little "screen time," but she may very well be an important character in the novel. It all depends on why Case runs out on her. Is it something about her that causes him to bolt, and if so, then what? Has Case changed from his time in Chiba City and how? Is it both or neither? Case never explains why he gave her the slip because the Turing Police soon catch up with him. So, dear reader, what do you think?