He took out his Zippo lighter and thumbed the flint, and the orange flame cast its halo glow through the darkness. Worried that it was low on fuel and would soon gutter out, he searched around for Hacker’s fallen lantern and found it, hoping that it wasn’t irreparably damaged. To his relief, after a few shakes and knocks it started working again. He put away the warm lighter and set the lantern down on the floor next to him as he took the pistol from Carter’s body and stuck both weapons in his belt. Carter and Banks each had a spare magazine in their pocket. Thirty-four more rounds of the same hollowpoints Hacker was using. Not sufficient ammo to start a war with, but plenty enough to put an end to Stuart’s operation. The dead men had phones, too, which Ben lifted as well. Next, picking the lantern up again, he made his way over to the mysterious hole in the wall that was all that remained of Boonzie’s presence in the dungeon.

How Boonzie had managed to work the stone block loose, Ben couldn’t begin to imagine. With no tools to work with, it must have taken him dozens of hours and left his fingers raw. There were dried bloodstains on the block, which stood up on end near the hole with a jagged chunk broken off one corner.

The bad smell was noticeably stronger over by the hole; Ben didn’t realise why at first, until he leaned in and examined it more closely by the lantern-light, and understood. Boonzie’s escape route was, literally, a tunnel: a large-diameter sewer pipe running through the castle foundations past the curve of the dungeon wall.

Ben shook his head in amazement at his friend’s resilience. Boonzie must have been drawn to the spot by the sound of water gushing through the pipe. Maybe the mortar holding in the block had become weakened by moisture leaking from some small crack over time. A few well-aimed kicks might have been enough to start the process of loosening it, before the endless labour of doggedly working it back and forth and inching it from its space. After he’d finally managed to work the block all the way loose he’d smashed it down on the dungeon floor to break off the smaller chunk, which he must have then used to bludgeon a hole in the pipe big enough to crawl into. It had been a desperate gamble taken by a desperate man. His escape through the sewer pipe must have been indescribable.

And now Ben was about to find out for himself. Because there was no way out of here except to follow in his friend’s footsteps. If it was good enough for Boonzie McCulloch, then it was good enough for him.