I sat and sang dead Ralfi's stolen program for three hours.

The mall runs forty kilometers from end, a ragged overlap of Fuller domes roofing what was once a suburban artery. If they turn off the arcs on a clean day. A gray approximation of sunlight filters through layers of acrylic, a view like the prison sketches of Giovanni Piranesi. The three southernmost kilometers roof Nighttown. Nighttown pays no taxes, no utilities. The neon arcs are dead, and the geodesics have been smoked black by decades of cooking fires. In the nearly total darkness of a Nighttown noon, who notices a few dozen mad children lost in the rafters?

We'd been climbing for two hours, up concrete stairs and steel ladders with perforated rungs, past abandoned gantries and dust-covered tools.

We'd started in what looked like a disused maintenance yard, stacked with triangular roofing segments. Everything there had been covered with that same uniform layer of spray bomb graffiti: gang names, dates back to the turn of the century. The graffiti followed us up, gradually thinning until a single name was repeated at intervals. LO TEK. In dripping black capitals.

'Who's Lo Tek?'

'Not us, boss.' She climbed a shivering aluminum ladder and vanished through a hole in a sheet of corrugated plastic. '"Low technique, low technology."' The plastic muffled her voice. I followed her up, nursing an aching wrist. 'Lo Teks, they'd think that shotgun trick of yours was effete.'An hour later I dragged myself up through another hole, this one sawed crookedly in a sagging sheet of plywood, and met my first Lo Tek.

'S okay,' Molly said, her hand brushing my shoulder. 'It's just Dog.

Hey, Dog.'

In the narrow beam of her taped flash, he regarded us with his one eye and slowly extruded a thick length of grayish tongue, licking huge canines. I wondered how they wrote off tooth-bud transplants from Dobermans as low technology. Immunosuppressive don't exactly grow on trees.