The sight greeting her was mind-blowing: a crystal-walled chamber resembling the mausoleum inside the Nephilim flying fortress, but on an infinitely grander scale. It was cone-shaped, widening as it rose, and stretched upwards for well over a hundred feet. Another spiral path, this one hewn from the glowing surface and paved with adamantium plates, circled the inner wall almost to the vaulted summit. Glassy stalagmites stabbed upwards from the edge of its lowest turns.

All around the chamber, held upside down in recesses within the walls as if cocooned by crystalline spiders, were the rest of the Nephilim.

Nina stared in shock at the unmoving figures. There were hundreds of them, entwined in the same glassy tendrils she had seen when Gadreel’s sarcophagus first opened. A legion of grey faces, trapped in the eternal sleep of the damned.

She had found Tartarus, the inescapable underground prison from Greek and Roman mythology – which also entombed the half-angelic Watchers from biblical apocrypha. Once again, a truth from before the dawn of known history, when Homo sapiens were little more than the animalistic slaves of the Veteres, had been mutated by time into part of human religion. The fallen angels were real.

And they were about to awaken.

Blood and torn flesh disfigured the luminous walls where a Nephilim woman had been blown apart by a grenade. The frozen figures around her were similarly mutilated, dead in their crystal cocoons. The priestess – not Sidona, Nina could tell from the remains of her clothing – had been standing before one of them. The glassy strands around the warrior’s corpse had withdrawn into the wall. The glow of the crystal around him was different from the others, turquoise in tint. Again, she had seen the same thing with Gadreel’s sarcophagus. The priestess had been watching the warrior’s revival when the grenade killed them both.

So where was the resurrection key?

She looked up, following the spiral to its top. Dark shapes were visible through a crystalline ledge protruding out to beneath the centre of the chamber’s ceiling. The qi tracker – and Sidona.

The high priestess hadn’t heard Zan falling. Too far away – or was she in a trance? It didn’t matter. She wasn’t yet aware of Nina’s presence.

The redhead ran up the spiral. The Veteres had had space for many more prisoners, empty recesses dotted between the occupied. She passed another warrior whose resurrection had begun, the gossamer strands partially reabsorbed. Based on her experience, it would take a few minutes for him to wake. He was not a threat – yet.