The detailed engineering and architectural plans on Tristan Dudley’s phone had given Ben a good idea of the layout of the crypts and hidden chambers beneath Karswell Hall. Now he followed the map in his head that he’d memorised earlier that day, and tracked through the house in search of the entrance to the tunnels.

According to the plans, the subterranean network carved out by Crowley and his disciples connected to the house via a wine cellar. After some hurried searching he found the iron-studded door to the cellar, secured with a stout lock that took five shots from his pistol to mangle into a twisted lump of useless metal. He kicked the door and it swung wide open on creaky hinges. The smell of dankness and decay came up from the cellar to greet him as he ran down a flight of stone steps, activating his weapon light to show the way. He saw flashes of dingy brickwork and the remnants of old wine casks piled up. A rat scuttled into a pile of debris at his approach.

Ben stalked through the cellar, gun at the ready. He noticed the tracks that had scuffed a broad path across the flagstone floor, the way a hunter picks up on a maneater’s spoor leading towards its lair. He followed the tracks. At the far side of the cellar, where the end wall would have been, a stone archway loomed above him. He cast the quivering white beam of his weapon light across the inscription carved into the arch in Gothic script: AVE SATANAS, DOMINUS ET MAGISTER TENEBRIS. Hail Satan, Lord and Master of the Darkness.

Ben passed under the archway and moved on. The same strange sickly-sweetish odour he’d sensed earlier in the house was wafting from the mouth of the tunnel, much stronger now. It smelled like death. Like the rancid breath from the jaws of hell. It made him feel nauseous as he jogged fast into the darkness, shining his bright white beam right and left to light the way.

The tunnel was long and deep and its walls were round and smooth. Ben had to wonder at the thousands of tons of concrete that must have gone into the building project. On he ran, passing doorways and secondary passages on both sides of him. He ignored them. Dudley’s plans showed that the main shaft of the crypt cut arrow-straight from the house, plunged deep underground beneath the lake and then narrowed to an upward shaft that emerged on the wooded island. He was following in the footsteps of the same grim journey made by the many innocents gruesomely murdered there by the Pandemonium Club in the name of their gods.