‘Not when you let a computer study the real values over the relative.’ Sam’s stern gaze was let down both by her elfin features and by wisps of bed hair. ‘The patterns of the signatures were more or less the same. But the energy spike in ’87 was larger by a factor of about ten.’

‘Ten times larger?’ Will breathed. ‘So the one up there is only a minnow by comparison.’

The information felt significant, but Sam was right; his brain was just too tired to make much headway.

Then his mobile rang, the tone cutting through the pre-dawn quiet. Sam looked at him, expectant. ‘It’s the Doctor,’ he said. As Sam groaned, he picked up.

‘Wavelengths, Will!’ the Doctor boomed in his ear. ‘I need to study the radiation signatures from the collector … reckon it’ll help us find Ace! Sorry, Dorothy. Although, that is ace news, isn’t it?’

‘You really think you can find her?’ Will almost laughed out loud.

‘I hope so! So! Radiation signatures …?’

‘You’re in luck,’ Will said. ‘Sam just did the maths. We’ll get right on to rolling out a data summary.’

Sam rolled over and buried her head in the pillow.

CHAPTER NINETEEN

Will had arranged to rendezvous with the Doctor at Dorothy’s batcave. Sam had agreed it was sensible for him to drop off the radar while the official investigation into his conduct was launched, at least until this business was over.

Well, ‘agreed’ was possibly too strong a word. She had shouted angrily that he was acting like an irresponsible teenager and that his career was finished whatever he did now, so why not go ahead and disappear like his old flame had done and leave her to hold everything together at the Space Defence Centre like she always did.

So that was exactly what he’d done, once she’d helped him compile the data on the radiation wave signatures of all the extraterrestrial craft to have come visiting, and held him close and kissed him goodbye and flung him out of the centre in the sleepy light of dawn.

Will had the windows open and the stereo blasting as he drove, keeping carefully to just a little over the speed limit. He couldn’t afford to be stopped, or risk a crash. He couldn’t be delayed, not now.

The Doctor and Yaz were already there by the time he’d arrived. They’d found what looked like an industrial steel sink ringed with pipes and cables: a regeneration cradle, the Doctor called it, something to put the juice back into the metal squid-thing, depleted after misadventures on the space station he chose not to ask much about.

Details didn’t matter. Finding Dorothy did.

Will showed the Doctor the summaries on his tablet.

‘So the station that came in 1987 gave a boost ten times greater than those in 2020?’ The Doctor frowned. ‘Funny. You’d think they’d have the same capacity … Come on.’