Theo studied the map in front of him, absorbing the network of lines and points and the stories they told. It wasn’t his first time seeing it of course, as every specialist underground engineer was trained on the layout and significance of the Tube. This was his first time here in person, however, and there’s something about the feeling of being in a place that no amount of experience can prepare you for.

“Central Line,” explained his liaison, Mark. “By Lancaster Gate.” He pointed up at the stations on the board to indicate.

Snapped out of his reverie, Theo felt somewhat like a lost tourist despite having been brought in as an expert. He nodded in acknowledgement. “What exactly happened here? In your own words,” he asked.

It was probably a false alarm. It usually was with London. A pioneer of underground systems, it had been designed with multiple failsafes and redundancies that had kept it mostly functional for over a century. It was also very heavily travelled, which helped maintain it. Still, when a situation occurs on any metro network around the world, it raises a flag. The events on the Central Line had raised enough to trigger an investigation.

“Official story is signal failure,” Mark began. “Again. God knows it happens enough on these lines. But it seemed to have been happening more and more often, particularly focused around Kensington. The guys never found anything too out of the ordinary, just your standard mechanical failure, but something about it just felt off to me.”

Theo nodded, recalling the slight pattern of incidents from his notes.

“So when they shut down Lancaster Gate to work on the lifts, I took the team out for a more thorough inspection. See if we could sort it out once and for all, before the locals got too restless. We swept the line looking for, hell, anything. I don’t know how long we had been out there for, but things suddenly got really quiet. You can usually hear some sort of distant rumble or whatever. I swear, the place stopped echoing.”

Mark paused his tale, weighing up how to describe what happened next. He took a swig of cold tea. “That’s when I heard it,” he continued. “A loud metallic bang, then another, and another, like something breaking through metal. For a minute I thought a train was coming and that’d be the end. It’s hard to lose that instinct, you know?”

Theo knew.

“We rush back to the cab, and it was dented. Like something had hit it at speed multiple times. It didn’t take us long to decide to get the fuck out of there. That’s when I reported it to the super, and that’s when you were called in.”