Erik reached for the control panel, then had to snatch his hand back again as the cat head tried to bite it. He giggled happily, tried again, and made a few small adjustments. The blazing mechanisms jumped and danced, pieces of solid light interacting on many levels, moving irrevocably towards one terrible configuration. The cat head howled, a long, rising sound that continued long after lungs would have given out. And then the cat’s jaws snapped together, its whiskers twitched, and its eyes locked on to something only they could see. The cat head spoke, but there was nothing human in its harsh yowling voice.

“Something new has come to Oxford Circus,” it said. “Or something very old. Something from the afterworlds has manifested in the tunnels, deep down in the dark. And it’s not alone, down there. Its mere presence is enough to stir up ghosts and demons and monsters. The darkness is alive. And it’s hungry.”

Erik looked at Natasha. “See? I told you!”

“Shut up. We already knew there was a powerful force loose in the station.”

“Still, something from the afterworlds, made flesh and therefore vulnerable . . .” Erik rubbed his hands gleefully. “Now that’s a prize worth having.”

“It’s cold, and it burns,” said the cat head. “It’s wild and fierce and free, and it will kill you.”

“You wish,” said Erik absently, and turned off the cube. The cat’s head fell silent, but its unblinking eyes still burned with hate.

“I’m hungry,” said Natasha.

“Eat your chicken legs,” said Erik.

“Hungry for ghosts,” said Natasha. “There’s nothing quite like them, nothing so . . . satisfying. I might even leave a few for you, this time.”

“You know I don’t indulge,” Erik said primly. “Nasty habit, and dangerous to your mental health. If you ever had any.”

“Prude,” said Natasha. “Scaredy-cat.”

Erik sniffed loudly but wouldn’t meet her eyes. “I value the integrity of my mind far too much to risk contaminating it with inferior thoughts and memories.” He gave in to curiosity and looked almost defiantly at Natasha. “I simply do not see what you people get out of it. Don’t you ever get . . . confused, with other people’s memories and identities suddenly crashing about inside your head?”

“Darling,” said Natasha, “that’s the good part. That’s the rush. That’s what makes them so very tasty.”

“You’re disgusting.”

“I know you are, but what am I?”