Banks reluctantly stepped to the edge of the hole and started clambering down the ladder, his footsteps resonating inside the hollow chamber. His lantern light darted around as he descended, and Ben was able to catch sight of parts of the curved inner walls, the stone blockwork wet and glistening with damp and condensation. Then Banks reached the bottom and shone his lantern upwards.

Hacker said to Ben, ‘You next.’ He stepped away to keep his safe margin of space as Ben approached the edge of the hole. Ben climbed down the ladder with two pistols pointing at him from above and a third from below. He was keeping his breathing slow and deep and steady, calming himself for whatever was about to happen next. Which could be a lot of things. Some of them bad, some of them worse.

Step by step, he descended into the pit of hell where his old friend had spent the last several days incarcerated in deplorable conditions, sick and maybe injured, and now set to die a horrible death if the Dishonourables had their way. The stench in the hole grew more choking with every downward rung of the ladder. Banks was standing at its foot looking up, his face contorted in disgust at the smell.

Ben stepped down one more rung and felt the solid floor underfoot. Banks backed away, keeping the pistol pointed at him and the light aimed in his face. ‘Move a muscle, twitch a finger and I’ll blow your fuckin’ brains out, get it?’

Boonzie still hadn’t made a sound. Ben tried to peer past the dazzling light shining in his face so he could search for his friend, but could make out only shadow and darkness. Above him, Hacker’s footsteps were ringing on the ladder rungs, quickly followed by Carter’s; and seconds later all four of them were standing inside the pit of the dungeon. Hacker shone his lantern around the chamber. ‘McCulloch?’

Ben stood very still with two guns pointed at his head. As he watched the sweep of Hacker’s lantern around the dungeon walls, he was steeling himself for the sight of his friend in God knew what kind of state.

But then two things happened that Ben couldn’t have foreseen.

The first was that Hacker’s lantern light completed its 360-degree sweep of the chamber without revealing anything but bare stone blockwork. Then it suddenly jerked to a halt and remained fixed and trembling on one spot. Not on the huddled and abject figure of a sick or dying prisoner – but on a neat rectangular hole in the wall where a stone block had been removed.

Ben’s heart jolted as if defibrillator pads had been pressed to his chest. The dungeon was empty. Boonzie was gone. Stuart’s plan had just become half-unravelled.

Hacker yelled out, ‘He’s not fucking here!’