They were in a large chamber, sparsely decorated, the walls bare rockcrete. To one side was a desk staffed with menials. To the other was the rank of elevators that rose up to the tower’s operational levels. The place was busy, stuffed with merchants, preceptors, security guards. There were more of the latter in place than he might have expected normally – probably a fallout from Vongella’s purge.

‘It’s been a long journey,’ said Zidarov, truthfully. ‘Somewhere I could… visit?’

The man looked briefly embarrassed. ‘Of course. This way.’

He showed him to a side entrance, then left him to enter the public hygiene-chambers. Zidarov found an empty cubicle, locked the door. He pulled out a little disc the size of a child’s palm, and locked it under the washbasin. Then he waited a minute or two before re-emerging.

‘Thanks,’ he said. ‘All yours.’

The elevator took them up seven levels. The majority of the tower was solid rockcrete, so that was still a long way up. As they ascended, Zidarov felt his ears pop. They emerged at the summit, several hundred feet into Alecto’s thick atmosphere. He was shown into a wide, open chamber, maybe twenty yards across. It was hexagonal, with every wall constructed of armourglass. The panorama was impressive – a hawk’s eye view over the entirety of the receiver-cradle below.

The menial in the scruffy uniform withdrew, closing the two swing-doors behind him. That left Zidarov alone with the chamber’s only other occupant, who was standing with her back to him, looking out across the vista. She was tall, slim, with silver hair tied up with a chain of pearls. She wore a sharp white suit. It might even have been real fabric – it had none of the shininess of synths.

Zidarov walked up to join her. Outside, the rain was hammering, thrown down from a churning mass of pale grey cloud. Far below, the entire city splayed out, drenched and dirty.

‘We have a scheduled descent in a moment, probator,’ said Rebeka Genova, Colossus platform’s supervisor. ‘I thought you might like to see it.’

Zidarov glanced around him. The chamber was surprisingly empty of furnishings. A long, low metal desk, some chairs, six cogitator housings all linked up with long cables, a set of clicking picter lenses with scheduled arrivals and departures. The coiled serpent of the city hung from the ceiling in a sculpture of beaten bronze, as ever beside the iron aquila of the Imperium.

‘What a nice thought,’ said Zidarov.

He ran a quick iris-scan of the chamber, making the sweep as he turned his head back. As expected, the place was stuffed with listening devices. Some of those might conceivably have been for the supervisor’s own benefit. It was impossible that they all were.