Macks had given Drusher a stablight, and carried one of her own. They walked together, their footsteps gritty and crisp on the ground, playing the beams around.

The Gardens of Tycho had not been a sophisticated collection. Drusher remembered the spectacular xeno-fauna halls of Thracian Primaris that he had visited as a young man. There, the pens and enclosures had been encoded to create perfect habitats for the precious specimens, often with their own atmospheres, their own gravities even.

Such expertise – and the money to realise it – had not been available on Tycho. These were simple cages and, in places, armoured holding tanks, where exotic creatures from the far-flung corners of the Imperium had lived out their days on Gershom in miserable confinement.

Drusher knew exactly how they felt.

‘If it’s been caged like this, Macks, it will perhaps have become psychotic,’ he said.

‘The animal?’

‘The animal. It’s common in poor conditions such as these. Animals held in crude cages often develop behavioural problems. They become unpredictable. Violent.’

‘But if it’s a predator anyway…’ she began.

‘Even predators have patterns. The need to hunt, to breed, to territorialise. Limit those things, and you break the pattern.’

‘That’s important why?’ she asked.

‘If this animal is a carnivore, and I would suspect as much, it isn’t feeding on its kills. Well, only minimally. It is killing simply to kill.’

‘Like the hill beast?’ she murmured, thinking back to that haunted winter in Outer Udar.

‘No,’ he said. ‘That beast was different. Killing was its behaviour. Here we have an aberration.’

As they walked further, Drusher began to see the awful damage done in the course of the war. Bomb-shattered pens, mounds of rubble, plasteel cages shorn from their mounting blocks.

And bones.

There were corpses in the intact pens too. Limp sacks of dried flesh, scattered vertebrae, the lingering stench of dung and decay. A row of wire domes that had once held rare birds was littered with bright feathers. Tufts of down caked the wire mesh, evidence of frantic, starving attempts to be free. They reminded Drusher of Baron Karne’s poultry coops.

‘We thought everything had died,’ Macks said. ‘The stink when we first came down here. I mean, nothing had been fed or cleaned out in months. Everything in a sealed cage was dead, except some kind of emaciated dromedary horse, which had been living off its own fat deposits, and even that died a few days after we freed it. And everything in the bombed cages we figured was wiped out, although there are some finch-monkeys loose in the Lower Bowery, freaking little things, and Falken swears he saw a grazer on Lemand Street one night, though I say he was drunk.’

‘So if something’s loose, it came from the bomb-damaged cages?’ Drusher said.