‘I don’t know,’ I say, not sure why I’m hiding Adam’s theory on imminent invasion from Sarah. I guess maybe I’m still trying to protect her. I quickly change the subject. ‘How’s Mark doing, anyway?’

‘He’s doing fine,’ Sarah replies. ‘He’s changed a lot.’

‘How so?’

Sarah hesitates. ‘I … it’s hard to explain.’

I don’t dwell for very long on the present state of Mark James. It isn’t what I want to talk about. Really, after nearly dying this afternoon, all I want is to hear Sarah’s voice.

‘I miss you,’ I say.

‘I miss you, too,’ Sarah replies. ‘After a long day of fighting alien invaders and unraveling international conspiracies, I wish we could just snuggle up on that old couch in my basement and watch a movie.’

That makes me laugh, the feeling bittersweet as I picture the kind of normal life Sarah and I might be leading if we weren’t trying to save the world.

‘Soon,’ I tell her, trying to sound confident.

‘I hope so,’ she replies.

I sense movement behind me and turn around to find Sam standing on the ruined porch of Adam’s house. He motions for me to come inside.

‘Sarah, I’ve gotta go,’ I say, feeling reluctant to hang up the phone. We’ve been checking in with each other every eight hours like we planned, and I feel a sense of relief every time I hear her voice. Every time I disconnect, I start thinking about the next time … the time when she won’t call. ‘Be careful, okay? Things might be getting pretty heavy soon.’

‘Things aren’t already heavy?’ she asks. ‘You be careful, too. I love you.’

I say good-bye to Sarah and tilt my head at Sam. He looks almost excited, like he’s gotten some good news in the last five minutes.

‘What’s up?’

‘Come down,’ he says. ‘We figured something out.’

I climb on to what’s left of the porch after this afternoon’s skirmish and follow Sam through the half-sunken doorway into the living room. The interior of the house matches the exterior – the perfect idea of human suburbia – except the furniture looks like it was arranged exactly as seen on the pages of a catalogue. There’s absolutely no sense of it being lived in. I try to imagine what it was like for Adam growing up here, try to picture him bashing little Piken action figures together on the floor, and just can’t do it.

At the back of the living room is a massive metal door secured by a series of locks operated by a keypad covered in Mogadorian symbols. The door is the one thing that breaks the suburban illusion and it’s actually kind of surprising to me that the Mogs didn’t try hiding it behind a bookcase or something. I guess they never thought their enemies would make it this far. The door is already open, unlocked by Adam earlier, and it’s through there that Sam and I descend into the tunnels beneath Ashwood Estates.

We walk down a long metal staircase, the phony homeliness above immediately replaced by sterile stainless steel and buzzing halogen lights. The labyrinthine network of tunnels beneath Ashwood is much more in keeping with my idea of the Mogadorians – functional and cold. It’s not quite as sprawling down here as the hollowed-out mountain in West Virginia, but it definitely puts Dulce Base to shame. I wonder how long it took them to carve all this out, the Mogs tunneling into the Earth during those years I was on the run with Henri, expanding their reach without us even realizing it.

There’s a jagged and long crack in the wall that starts about halfway down the steps and runs ahead deeper into the tunnels. Sam reaches out to drag his hand along it, coating his fingers with concrete dust.

‘We’re sure this place isn’t going to collapse, right?’

‘Adam doesn’t think so,’ Sam replies, clapping his hands clean, the noise echoing. ‘It creeps me out down here, though. Seriously claustrophobic.’

‘Don’t worry. We won’t be staying long.’

We pass other cracks as we navigate the twisting hallways, places where the foundation shifted, broken sections of concrete grinding against each other. The damage was caused the last time Adam was here, when he unleashed his earthquake Legacy to rescue Malcolm. There are some hallways where the ceilings have outright collapsed.

Down the hall, we pass by a large, well-lit room that looks like it might have been a laboratory at one point, lots of nozzles and levers and worktables, but no equipment. Everything must have gotten destroyed in Adam’s attack, and the Mog salvage team never got the chance to replace it. Next to the lab, we pass a row of oppressive eight-by-eight rooms with thick doors made from bulletproof glass. Cells. All of them currently unoccupied.

‘The archives are up here,’ Sam tells me. ‘Dad’s been in there nonstop. The Mogs recorded everything.’

We stop by a small room – almost like an office – with a huge bank of monitors. Malcolm sits behind the room’s single computer terminal, bleary-eyed from watching who knows how many hours of footage. On-screen, a Mogadorian scout speaks directly into the camera.

‘It has been three days since we leaked rumors of a Loric presence in Buenos Aires,’ the scout reports. ‘There has yet to be any sign of Garde, but surveillance continues –’

Malcolm pauses the video when he notices us, rubbing his eyes.

‘Find anything useful?’ I ask.

Malcolm shakes his head and pulls up a list of files on the computer. He brushes a finger down the touch screen, and the files begin an endless scroll. There are thousands of them, and all their titles are in Mogadorian.