Metal scaffolding replaced the sky, smoke collecting around the rafters as cold drops, of what Henry hoped to be water, fell like raindrops. He followed Gabriel along the alleyway, the door creaking shut behind him. It led onto a cobbled street with two storey buildings either side, that melded with the roof and the clouds. The structures were a tour de force of architecture from modern to Victorian, and even Tudor designed buildings, all crammed next to one another. Walkways along the second floor wrapped around street corners, disappearing into the distance as catwalks stretched across the streets, like rope bridges across a ravine. At street level, fabric awnings, ragged and dulled with age, spilled out onto the street, only separated by the narrowest of margins from oil drums set alight, as groups of people gathered around them against the cold.

“Welcome to the under-city market,” Gabriel said, a little too much like Willy Wonka introducing the Chocolate Factory than he probably intended to.

“Where are we?” Henry said.

“The under-city market,” Gabriel said, mockingly slow.

Henry figured this was going to be a common theme with Gabriel, the teasing of information, but he played along anyway.

“And where is the under-city market?”

“This is a safe place for alternates. They can be open about their powers here and trade goods that you can’t get in human cities. The London under-city has grown quite large over the centuries, connecting to a fair few human markets and streets along the way. Look here.”

Gabriel crossed the street toward a darkly lit alleyway that ended in a brick wall.

“Human markets?” Henry said.

“Yes. You have humans and you have alternates, who are magic-folk. You are the latter, as I explained before.”

“I am human.”

“If you say so,” Gabriel said with a smug smile.

“Whatever. What exactly am I supposed to be looking at?” Henry said dismissively.

“You see the crack in the pavement? Follow it down the alley.”

“To where? What am I looking at?”

“Concentrate.”

“This is ridiculous, are you winding me up?”

“Just do it,” Gabriel said, a slight redness adorning his pale cheeks.

Henry looked at the pavement by his feet. The slabs were cracked in such a way as to produce a thin line that meandered down the alleyway. It probably ended in a wall. It had to really. Or it ended somewhere that wasn't important at all, not even worth thinking about it.

“Shall we carry on?” Henry said.

“Take another look,” Gabriel said, his voice firm.

What was he getting so uptight about? Henry stared at the crack in the paving once again and followed it along the alleyway, but this time focussing on every slight deviation the crack made as it meandered towards the wall. As he got further towards the end of the alleyway, Henry noticed it. Something he couldn’t quite put his finger on, but he was sure of the sensation. It was as if his attention was being purposefully diverted, his mind encouraged to wander from the task at hand, the feeling stronger for every inch he moved along the crack in the floor. Henry traced the line back towards himself and found his attention return, but going the other way was a different matter entirely.

He had to concentrate.

Henry focused again on the crack in the pavement with an intensity that felt stupid, following it with as much vehemence as he could muster. The line flowed from his feet, along the floor, twisting and turning with the broken paving slabs, passing beyond where the wall should have been. It travelled via the surface of a pond, except not one that lay on the ground, but vertically against the wall. Ripples cascaded across the surface, like a pool of mercury, and, in its moments of serenity, Henry saw glimpses of the brick wall again. The crack itself wobbled straight through the translucent fish pond and Henry continued to follow it, with renewed focus, until it came to an end at the most peculiar of items.