“Maybe you should be taking more pills, not less,” said JC.

“Or,” said Happy, leaning forward, his voice dropping into a conspiratorial whisper, “could it actually be even worse than that? Could it be that the highest levels of the Carnacki Institute have been doing things they shouldn’t? There are rumours . . . There are those who say that, possibly, there are people in the Institute on a much higher level than we have access to who approved an operation they shouldn’t have; and as a result, something really bad has happened, something that those very people are desperately trying to put right before anyone finds out . . . before the whole world falls apart. Could this whole situation, this unprecedented Code One Haunting right in the heart of London, be the result of a Major Working gone terribly wrong? And that’s why we’re here, rather than one of the A teams, because the Boss wants this handled quietly, by entirely expendable agents?”

“Okay,” said JC. “You’re really starting to worry me now.”

“Good,” said Happy. “Join the club. We’ve got our own badges and everything. Now take it a step further. What if there’s another group? Some third organisation that’s so secret even we don’t know about them, working in the shadows of the world for their own dark reasons?”

“Stop that,” JC said firmly. “Stop that right now before my brains start to leak out my ears. That way paranoia lies.”

“Welcome to my world,” said Happy.

“You’ve given me a headache now,” said Melody, accusingly.

“I’ve got a pill for that,” said Happy.

Melody let out a sudden bark of laughter. “Like I’d ever touch anything you use. I take my consciousness straight, not altered, thank you very much.”

Happy sniffed. “Don’t know what you’re missing.”

And then all three of them looked round sharply, staring into the right-hand tunnel-mouth. From out of the impenetrable darkness came the sound of an approaching train. A low, muted roar, drawing steadily closer. Except that this part of the Tube network had been shut down, all regular trains diverted to other lines and other stations. The three ghost finders moved instinctively closer to each other, staring into the dark tunnel-mouth as the sound of the train grew steadily louder.

“Is it coming here?” said JC. “To this platform?”

Melody looked quickly across her sensor readings. “Coming right at us, JC. Damn, it’s moving fast.”

Happy stepped reluctantly away from the others, as though drawn to the dark tunnel-mouth. He moved slowly forward, step by step, listening rather than looking. JC gestured for Melody to be quiet. Happy stopped at the very end of the platform, a few feet short of the gaping darkness.

“It’s almost here. I can see a light, coming this way. The rail tracks are vibrating. I’d say this is almost certainly a real train. But it . . . feels wrong.”