JOHNNY CYBERPUNK

I didn't really understand this story that much but what did understand is that the story takes place in the future where there are many people who sell drugs and many people have had a sex change. The story involves a man called Johnny who has a data file implanted in his brain which wants him to go to a specific destination. Along the way there is cyborg dolphin type of creature who i believe is taking down Johnny for that file. That is about where I understood the story, from then on I was pretty lost.