It was difficult to believe that this was the same person that she had travelled with all those years ago … She’d known about regeneration – the Doctor had explained it to her – but it was one thing to understand the theory, quite another to witness it first hand. There was nothing that even remotely resembled her Doctor. The hair was different, the manner was different, the height, the accent …

Oh, and the fact that he’d regenerated into a woman, of course.

And it wasn’t just the Doctor that had changed. The TARDIS was virtually unrecognisable from the ship that Ace had once travelled in. Gone were the clean white walls, with their softly glowing roundels, replaced with dark, perforated metal sheets, their upper edges swathed in misty shadows. Gone too was the sleek hexagonal console; the mushroom-shaped control centre that now dominated the room looked as though it had been hewn from hunks of crystal; the huge, quartz-like fingers that arched overhead glowing from within with a warm amber light.

The entire place was vast – far larger than it had been. Mind you, it had only been the two of them back then; these days the Doctor seemed to be travelling with a small army. She glanced over to where her three fellow human travellers were talking in hushed tones on the far side of the room. The older man, Graham, had seemed friendly enough, but the other two – Yaz and Ryan – seemed to be a little wary of her.

Ace couldn’t blame them. She had always been very protective of her Doctor. She smiled as she recalled the outrage she had felt when Brigadier Lethbridge-Stewart had referred to her as ‘the latest one’.

Weird, she thought. I’m thinking of myself as Ace again …

She regarded the Doctor once more. How many people had he … she travelled with since their time together, she wondered? How many different faces since they had parted company all those years ago? Would she still remember the circumstances of their parting? Would she recall the details of their time together at all?

As if knowing that she was being scrutinised, the Doctor lifted her head, staring straight across the room at her. Ace felt her cheeks flush, but if the Doctor noticed she didn’t say anything.

‘So, are you going to give me the coordinates for this super-secret base of yours, or shall I just dig out an OS map of Oxfordshire and you can point?’

Pulling her phone from her jeans pocket, Ace opened up the maps app, typed in Kirkwood Farm then crossed to the Doctor. ‘Try not to land on top of the Triumph.’

The Doctor took the phone and grinned at her. ‘Smashing.’

As the Doctor started setting coordinates, Graham wandered over to Ace’s side, a concerned look on his face. ‘What about your mate?’ he asked. ‘Is he going to be all right on his own?’