Pattern Recognition by William Gibson

might be.
    Down Parkway and over to little Inverness, the market street that runs its single block into Camden. She knows a café here, a French place. Remembering breakfast there with Damien.
    Passing record and comics shops, windows papered with flyers (where she half looks for, but does not find, the kiss).
    Here it is: faux-French with real French waiting tables. Chunnel kids, guest workers.
    The first thing she sees, going in, is Voytek, seated at a table with silver-haired Billy Prion, the former lead singer of a band called BSE.
    She’s long kept track of certain obscure mirror-world pop figures, not because they interest her in themselves but because their careers can be so compressed, so eerily quantum-brief, like particles whose existence can only be proven, after the fact, by streaks detected on specially sensitized plates at the bottom of disused salt mines.
    Billy Prion’s streak is by reason of his having deliberately had the leftside of his mouth paralyzed with Botox for the first BSE gigs, and because, when Margot was taking her NYU extension course in disease-as-metaphor, Cayce had suggested she do something with his mouth. Margot, struggling to outline a paper in which Bigend was the disease she needed to find a metaphor for, hadn’t been interested.
    Having automatically registered Prion media hits ever since, she knows that BSE had broken up, and that he’d been briefly rumored to be romantically involved with that Finnish girl, the one whose band had been called Velcro Kitty until the trademark lawyers arrived.
    As she passes their table, she sees that Voytek has a scrawled tarot of spiral-bound notebooks spread out around the remains of his breakfast, everything executed in red ballpoint. Diagrams, with lots of linked rectangles. From what she sees of Prion’s mouth, the cosmetic toxin seems long since to have worn off. He isn’t smiling, but if he were, it would probably be symmetrical. Voytek is quietly explaining something, his brow wrinkled with concentration.
    An irritable-looking girl with red-rimmed eyes and very red lipstick fans a menu in her face, gesturing curtly toward a table farther in the rear. Seated, not bothering with the menu, Cayce orders coffee, eggs, and sausage, all in her best bad French.
    The girl looks at her in amazed revulsion, as though Cayce were a cat bringing up a particularly repellant hairball.
    “All right,” says Cayce, under her breath, to the girl’s receding back, “be French.”
    But her coffee does arrive, and is excellent, as do her eggs and sausage, very good as well, and when she’s finished she looks up to see Voytek staring at her. Prion is gone.
    “Casey,” he says, remembering but getting it wrong.
    “That was Billy Prion, wasn’t it?”
    “I join you?”
    “Please.”
    He repacks his spiral-bound notebooks, closing each one and tucking it carefully away into his shoulder pouch, and crosses to her table.
    “Is Billy Prion a friend of yours?”
    “Owns gallery. I need space to show ZX 81 project.”
    “Is it finished?”
    “I am still collecting ZX 81.”
    “How many do you need?”
    “Many. Patronage also.”
    “Is Billy in the patronage business as well?”
    “No. You work for large corporation? They wish to learn of my project?”
    “I’m freelance.”
    “But you are here to work?”
    “Yes. For an advertising agency.”
    He adjusts the pouch on his lap. “Saatchi?”
    “No. Voytek, do you know anything about watermarking?”
    He nods. “Yes?”
    “Steganography?”
    “Yes?”
    “What might it mean if something, say a segment of digitized video, is watermarked with a number?”
    “Is visible?”
    “Not ordinarily, I don’t think. Concealed?”
    “That is the steganography, the concealment. Multi-digit number?”
    “Maybe.”
    “Can be code supplied to client by watermarking firm. Firm sells client stego-encrypted watermark and means to conceal. Check web for that number. If client’s image or video has been