Valkyrie stayed by the door, making sure no one was going to walk in on them. She tried to keep her eyes from the spot where Stephanie had been killed, but her gaze kept dropping, kept picturing her there. Images surfaced of what her final few moments must have been like. To be that scared and that alone …

“You have three days, nineteen hours and one minute left,” the Engineer said. “Plenty of time to decide who will give their soul.”

“We’re not here to shut off the Accelerator,” Skulduggery said, “we’re here to use it. Is that possible?”

“Of course.”

“Would that affect the time we have left? From what I know of its processes, using it at this late stage could speed up the overload.”

“You are quite correct,” said the Engineer. “A full boost to your power would have a cumulative effect on the Accelerator’s systems. If you wish to avoid that, I can reduce the level to which your abilities are enhanced. Instead of you reaching one hundred per cent of enhancement, you would reach sixty-three per cent. Still a significant boost, if I do say so.”

Skulduggery looked back at Valkyrie. “Thoughts?”

“Many and magnificent,” she said. “But you’re the one who reckons we need all the help we can get.”

“To start down this road, though,” Skulduggery said. “It’s dangerous.”

“The roads we take usually are.”

“You heard the lady,” Skulduggery said to the Engineer. “But before we do this, can I count on your discretion?”

“I am a robot,” said the Engineer. “I do not gossip. Please step into the Accelerator.”

“Actually, I’m going to stay out here,” Skulduggery said, and began unbuttoning his shirt. Tendrils of shadows seeped out from between his ribs. They collected in his outstretched hand, forming a spinning sphere of darkness that grew in mass the more the shadows flowed. Finally, the tendrils trailed off, and Lord Vile’s power drifted from Skulduggery’s hand to the Accelerator. It hovered over the dais, which began to tremble. A glow spread beneath the skin of the machine, and the sphere spun faster, expanding and contracting at an astonishing rate.

The glow in the Accelerator became a light that hurt Valkyrie’s eyes. She looked up and down the corridor. No one coming. She examined her own shadow, stark against the wall. Then the shadow began to fade as the light behind her grew dim.

She looked back. The Accelerator had powered down, but the sphere was still spinning so fast it looked to be in constant danger of unravelling. She knew it was taking all of Skulduggery’s self-control to keep it in one piece.

It darted to Skulduggery’s hand. Now was the moment when it could all go horribly wrong. If the shadows morphed into armour and enveloped him, a supercharged Lord Vile would destroy this world just as readily as Darquesse.

Skulduggery’s head twitched.