We finally reach the bottom of the stairs, and exit the stairwell into a large rectangular hallway totally covered in polished chrome. There are two restricted access doors set into the wall in front of us, like steel sentinels standing between us and the labs, and, hopefully, some of the answers we need. The door on the left has a gleaming XGen sign attached to it, so we head there first. Karim manages to crack the code without too much trouble, and I’m wondering if I should be more careful about accessing anything private in front of him from now on. The door slides open with a swish, and we step into an area lit by the blueish light coming from a bank of about twenty monitors that cover the whole of the far right wall, all showing error messages.

‘I guess Mum didn’t have a chance to get XGen back on.’ Karim runs over to the monitors and peers at a screen. The bright ceiling lights flicker on, leaving us exposed in the open-plan room. ‘Weird, cos this error is basic. I reckon even I could fix it.’ 76

‘Maybe we should do it?’ Kat says. ‘It would be good to have some wifi right now.’

‘I’d need a bit of time, which we don’t have,’ Karim says. ‘Plus, we’d need to get onto the roof and reboot the masts.’

The XGen area is huge, with desks set up in groups of four, and a chest-height counter running all the way around three of the walls, covered in equipment that looks like the kind of thing you’d expect to find in NASA. The furthest wall has doors leading to separate office cubicles. Everything is silver and white.

‘It’s like being inside a fridge,’ I say. ‘We’re way too visible – we need to be quick.’

‘More jogging,’ Karim says, starting forwards up the central aisle, towards the office doors. It’s the only place his mum could be.

‘I wonder what all this equipment does.’ Kat gazes around at the piles of science stuff. ‘Scientists aren’t very tidy, are they?’

‘One of the rooms at the end is a clean area,’ Karim says. ‘But the rest of this place is like the inside of a hoarder’s garage.’

I scan the area as well as I can, noticing that there’s a sprinkler system down here, the same as 77 up in the Cake, and that it clearly hasn’t gone off. There are no signs of damage caused by the explosion, apart from a few things on the floor, including some of the XGen signal beacons that we all have attached to our houses.

‘The beacons didn’t smash when they fell off the counter,’ I say, surprised because they have what looks like a cylindrical glass casing around them.