‘Why are they killing?’ Bequin asked me. ‘All these years, in secret ritual?’

‘I don’t know.’

‘You do, Eisenhorn. You so do!’

‘Very well. I can guess. The fellow worker who jokes at the Emperor’s expense and makes your fragile sanity imagine he is tainted with the warp. The rug-maker whose patterns suggest to you the secret encoding of Chaos symbols. The midwife you decide is spawning the offspring of the Archenemy in the mid-rise maternity hall. The travelling evangelist who seems just too damn fired up to be safe.’

She looked down at the floor of the Land Speeder. ‘They see daemons everywhere.’

‘In everything. In every one. And, so help them, they believe they are doing the Emperor’s work by killing. They trust no one, so they daren’t alert the authorities. They take the eyes, the hands and the tongue... all the organs of communication, any way the Archenemy might transmit his foul lies. And then they destroy the brain and heart, the organs which common soldier myth declares must harbour daemons.’

‘So where are we going now?’ she asked.

‘Another hunch.’

The Guildhall of the Sameter Agricultural Fraternity was a massive ragstone building on Furnace Street, its facade decaying from the ministrations of smog and acid rain. It had been disused for over two decades.

Its last duty had been to serve as a recruitment post of the Sameter Ninth during the founding. In its long hallways, the men and women of the Ninth had signed their names, collected their starchy new fatigues, and pledged their battle oath to the God-Emperor of mankind.

At certain times, under certain circumstances, when a proper altar to the Emperor is not available, Guard officers improvise in order to conduct their ceremonies. An Imperial eagle, an aquila standard, is suspended from a wall, and a sacred spot is marked on the floor beneath in yellow chalk.

The guildhall was not a consecrated building. The founding must have been the first time the young volunteers of Urbitane had seen that done. They’d made their vows to a yellow chalk cross and a dangling aquila.

Wrex was leading three fire-teams of armed Arbites, but I went in with Midas and Fischig first, quietly. Bequin and Aemos stayed by our vehicle. Midas was carrying his matched needle pistols, and Fischig an auto shotgun. I clipped a slab-pattern magazine full of fresh rounds into the precious bolt pistol given to me by Brytnoth of the Adeptus Astartes Deathwatch Chapter.

We pushed open the boarded doors of the decaying structure and edged down the dank corridors. Rainwater pattered from the roof, and the marble floor was spotted and eaten by collected acid.

We could hear the singing. A couple of dozen voices uttering the Battle Hymn of the Golden Throne.