‘It shouldn’t have been any of you,’ the Doctor said. ‘I should’ve found another way …’

‘Don’t,’ Yaz said softly. ‘It’s them you’ll find. Ryan and Chantelle and Kim … and Ace, too.’

‘Ace.’ The Doctor looked suddenly heartbroken. ‘You know how much I can gabble on, Yaz. You know how good I am at talking. I once talked a Dalek to death. An actual Dalek! And Ace was with me then, right here in London, 60-odd years ago … Good God, all the talking I’ve done. But, you know, trying to talk to Ace … where were the words?’ She shook her head, baffled. ‘I’m pretty good at uncovering things. I’ve discovered the rarest things in the strangest places, clear across the cosmos. But the right words to say to that woman? Nope. Never. She was sat beside me in the car and I still couldn’t find them.’

Yaz felt a twinge of jealousy at the strength of the Doctor’s sorrow, but it didn’t stop her sympathetic smile. ‘It isn’t too late,’ she said firmly. ‘You’d have been proud of her, you know. Helping to protect me, fighting off those things with just a baseball bat …’

‘Baseball bat?’ The Doctor stared suddenly into space, like someone in a cheesy film having a flashback. ‘She used a bat? What did it look like?’

‘Silver,’ said Yaz. ‘Had a—’

‘Black handle?’ The Doctor jumped up. ‘Then she used it! She used the bat! The more-than-a-bat.’

‘Doctor, what are you on about?’

‘That bat – it was affected at a subatomic level by an incredibly advanced piece of technology.’ She was pacing the room. ‘Boosted its percussive powers, made it into a kind of super-bat. I managed to break it, of course, you know me, always breaking stuff. But I had it fixed up, good as new, and I gave it back to her …’ The Doctor stopped walking. ‘On the day she left.’

‘Well, she used the hell out of it. Saw off a ton of those Ratt things.’

‘Yes! And she was still holding it when she disappeared?’

‘I’m pretty sure, yeah.’

‘Brilliant! Perfect!’ The Doctor was beaming. ‘Don’t you see? The bat’s bristling with distinctive alien energies. I might be able to pick up its trail and lock down the location of Ace, and Chantelle and Kim and all those poor souls who’ve been going missing from the streets …!’

‘What about Ryan and Graham?’

‘I’m gonna find them too. I’m already scanning.’ The Doctor frowned. ‘I wish I knew why.’

‘Why you’re scanning for Ryan and Graham?’

‘Why the Astingir took them prisoner. They’re not a bloodthirsty species – unless they suspect they’re dealing with friends of the Wraiths.’

‘At least you know where those horse-things will be making for,’ Yaz reminded her. ‘Same as us: whoever, or whatever, is behind all this.’