The traitor battleship had given up all attempt at disguising its whereabouts, its commander confident that the Ultramarines vessel had been utterly ensnared in the ambush. Pulsing low-energy navigational shields shunted aside debris and gas, creating a bow wave of stellar detritus that marked its accelerating passage through the cloud.

The distinctive signature of the laser conversion engines of the lance batteries supported the reports of the vessel’s primary armament. Bigger than the Ultramarines vessel, itself three miles long, the attacking battleship was also a specialist ship-hunter. Though not especially powerful, the secondary batteries would still be capable enough to overload the void shields of a cruiser-class target with one or two full salvoes. Unprotected, the prey would be cut open by accurate lance fire; shield generators, engines, environment control all pinpointed by ancient scanners and firing metriculators more powerful than anything aboard the Ithraca’s Vengeance.

In contrast, the Ultramarines warship was dedicated to boarding attack and orbital support. It could hold its own in a fight with a similar-sized enemy or two but lacked the range of a true ship-of-the-line. Flight bays took up more room than gun batteries, and with the gunships launched and a good proportion of the fighting complement on the enemy lure, the Ithraca’s Vengeance had little with which to strike at long range.

‘It is a convoluted plan, risky, with a low chance of success,’ remarked Lerok. ‘Damned sneaky, though. You must have your own share of ­cunning to have worked it out, lieutenant.’

‘On the contrary, the risk is slight,’ Praxa­medes replied. Speaking helped distract his thoughts from the motor-function tasks he had to complete. If he had to think about his fingers moving across the runepads they felt slow and clumsy. ‘Assuming that if our enemies in this sector had the resources to fully crew two destroyers and a grand cruiser they would do so, giving them a skeleton complement and acting as bait is the most efficient use of what would otherwise be empty materiel.’

With the trap sprung, there was no need to dedicate a complete sensor array to monitoring the gas and dust cloud. Praxa­medes powered it down, rerouting the energy back to firepower targeting matrices.

‘It’s also not through any personal insight that I uncovered the subter­fuge. In fact, it was Lieutenant Nem­etus’ instincts that were the first clue that all was not well. His insight was correct but his conclusions were not bold enough. I’ve unpicked the enemy plan only through diligent observation of the facts, in retrospect.’ He looked at the range to the incoming battleship and checked the chronometer. ‘Though too late, possibly.’

Moving to the neighbouring terminal, Praxa­medes inspected the recali­bration of the telemetric array. He trusted Lerok would have carried out the calculations impeccably but it was his responsibility, and therefore his duty, to confirm them.