Kim was the first to buck and scream as his body fell away from that of the Wraith beneath him as it flickered into nothing. All around the chamber, the Wraiths were dissolving, the humans on their backs shucked off like old skins, left to crumple to the floor. Graham and Ryan ran over to check on them. Yaz dropped the bat and hurried to help.

Masst stomped a hoof on the ground as if spooked, as he and his comrades stared about in disbelief. ‘The Wraiths return to the hell we made for them … of their own accord?’

‘People change. Hearts change. Minds change. Just look at you.’ The Doctor spoke tersely, her eye on Ace and the Wraith Queen. Ace’s whole body shook and contorted as the alien became a blur of shadow movement, shaking like a wet dog drying its fur. Ace toppled to the floor, and the Doctor rushed to her. Chantelle ran over as well.

‘Ace?’ The Doctor felt for a pulse – found a strong one – and stared down at her old friend.

‘You’ll be all right,’ Chantelle said encouragingly.

‘Tell that to what’s left of my brain, will you?’ Ace looked up at the Doctor groggily. ‘She let me go. The Wraith Queen …’

‘Yes. It was her choice. She chose right.’ When the Doctor looked back at the Queen, she had disappeared along with the other Wraiths that had been revived by Halogi-Kari.

Halogi-Kari?

He had disappeared too.

There were only black bloodstains now where he’d been lying on the ground, dripping away in a trail.

‘That Harbinger,’ the Doctor said suddenly. ‘The thing behind all of this. Where did Halogi-Kari go?’

Ryan, Yaz and Graham stared around anxiously.

Ace used the Doctor’s wrist to yank herself up. ‘Don’t worry, Professor.’ Getting unsteadily to her feet, she scooped up the baseball bat from the floor and staggered off into the shadows after the spats of blood. ‘I’ll find him.’

‘Ace!’ the Doctor shouted. ‘You’re not thinking straight …’

‘Go after her,’ Yaz said, struggling to arrange an unconscious woman into the recovery position. ‘We’ll keep an eye on Kim and the others here.’

‘Yeah, we’re on it, Doc,’ Graham added, helping Ryan with more of the fallen abductees. ‘We’ll do what we can.’

‘Chantelle, give us a hand, yeah?’ said Ryan. To his amazement, Masst came over to help too, while his infantry troops stood guard beside their unconscious commander.

‘I’ll be back!’ And the Doctor ran from the room, after Ace.

It didn’t take Ace long to find Halogi-Kari; she felt in a bad way, but clearly he felt worse. He’d crept out of a hidden exit in the Quantum chamber but was too weak from his wound to get far. Sobbing with pain, he had come to a halt in the corridor beyond, trembling in the middle of the flagstones.