Since Beltane, rain or shine (she seemed impervious to either) she had always ridden abroad like that. She was an intensified symbol of the Angel's power and men quailed before it. But she insisted on being its unique focus. When Jenny, the ex-Banwell nurse, riding with her one morning, had presumed to strip off her own shirt in imitation of her leader, Karen had merely looked at her in commanding silence. Jenny had flushed and replaced her shirt. Since then, no one had dared.

Today, jumping from the saddle as she arrived at the Henge a length behind John, she was the laughing warrior queen. The escort stayed respectfully beyond the encircling earthwork while John and Karen walked together among the huge sarsen trilithons, recovering their breath after the hard ride.

'I like your idea, John,' she said after a while. 'What did you call it? – "testing our heavy artillery"… Yes.'

'It almost frightens me,' John admitted. 'There's so much power here. Have we the strength to handle it?'

'Strength? After all we've achieved?'

'Even after that.'

The sun had disappeared behind a heavy bank of cloud and the lowering greyness reinforced John's doubts. His question had been almost rhetorical, for until then Stonehenge had merely challenged him, not troubled him. But suddenly, in retrospect, it was no longer rhetorical. John shuddered.

Karen walked over to the Altar Stone at the focus of the bluestone horseshoe. She fingered it for a moment and then lay face upwards upon it throwing back her hair. She smiled serenely up at the sky. 'I dare anything that the Henge can do.'

'Don't try to frighten me with melodramatics,' John said, covering his unease with casualness. 'In spite of popular belief, that was not a sacrificial altar. The evidence is that it once stood upright.'

'A fallen phallus. All the more appropriate as an execution altar.'

'You mean Bill Lazenby?' John was no longer casual. 'God, Karen – we've never done that before.' ‘We have killed before.' 'But ritual human sacrifice…'

'Bill has to die – you've said so yourself. Why not make his death serve a purpose? That would be a real test of our "heavy artillery".'

He looked down at her, fascinated and half-repelled, knowing that in their own terms she was right and almost despising himself for his reluctance. There were no half-measures possible, along the course to which they were committed. Yet still…

As he gazed, the sun broke through, bathing Karen and the Altar Stone in unexpected light. It was surely a sign, an endorsement of her intent. But could she draw the others along with her?… Most of them, yes, without hesitation, but one or two might baulk. His own support, he knew, would swing the balance; together they could command the Angels of Lucifer, as they had done from the start. If he failed her now, what breaches would he open?

'Very well, Karen. Tomorrow at dawn? New moon's the day after tomorrow, so it'll still be in the waning phase.'

'Tomorrow at dawn,' Karen said.

The eastern horizon was clear, with only the thinnest gauze of morning mist hugging it, so there would be no difficulty about timing the sacrifice. The Angels of Lucifer, their bodies glistening with the belladonna 'flying ointment', insulatory and hallucinatory, which Stanley Friell had prepared for them, danced in a wild ring widdershins between the outer ring and the horseshoe, keening and yelping; they had been at it for half an hour, enraptured and tireless, a dynamo of power that built and built, a charge awaiting detonation by the sacrifice, and ready to detonate in turn the vastly greater power locked in the ancient stones.

Inside the great horseshoes of trilithons were only Karen, John and Sonia the Maiden, grouped around the victim spreadeagled on the Altar Stone. There had been no need to bind him, for Stanley had prescribed for him too, with a dose that paralysed his limbs but left him conscious and wide-eyed. The Maiden stood behind him, stroking his head and shoulders, crooning to him, whispering flattery to him, telling him what a fine man he was, what a worthy sacrifice, filling his field of view with a last inverted vision of the living. John faced East across the Altar Stone, awaiting the first glimpse of the sun, ready to give the command to Karen as she stood opposite him, ceremonially astride with the knife held high.

A sliver of golden fire flickered on the horizon, and John cried: 'Now!'

As the blood pulsed on to the Altar Stone, Karen led them to join the ring of dancers, the red knife still in her hand, laughing in exultation as the earth shook beneath them and the towering megaliths groaned.

'The epicentre was in the area of Salisbury Plain,' Professor Arklow told Harley. 'A strange phenomenon. It could be felt as a slight physical sensation in the Cardiff and Manchester Beehives – and, as you know, here in London -but not apparently in the more distant Beehives. And yet I've had no reports of actual damage. Have you, Sir Reginald?'

‘Not so far, Professor. All the Beehives reported at once, of course – that's an established drill whenever the seismo-graphic duty officers report a sizeable tremor. All negative, except that as you say Cardiff and Manchester felt it. But agents on Surface within reach of radio points in the area have been reporting all morning, as well. They all say the same; considerable public alarm, naturally, but only trivial damage… What's your prognosis? Are we in for more?'

That's what I mean by a strange phenomenon,' the professor said. 'After the past few months, we pride ourselves on having become more skilled than ever on reading the signs. A tremor of that magnitude should have given us warning. It did not. I've even been back over the last few days' recordings to see if we'd missed anything but there was nothing. The tremor did not fit into any normal pattern nor has it been followed by any normal aftermath. It just happened, Sir Reginald. And to be frank with you, as a scientist I find that most disturbing. I keep asking myself: "Why?" – and finding no answers… What's so unusual about Salisbury Plain?'

I have a very good idea, Harley smiled to himself. But if I told you, my dear professor, you would not believe me.

Moira sat bolt upright in bed, jerked awake by a vertiginous awareness of evil. Her movement woke Dan, who sat up beside her, looked puzzled and grasped her hand.

'Did you feel it?' she asked as the wave subsided.

'I felt something. Something very nasty. From over there.' He pointed south-east and Moira nodded. Although Dan was less psychically sensitive than herself, she knew from long experience that he had a better sense of direction. 'Savernake Forest?'

'Could be.' He was already out of bed and pulling on clothes. 'Hadn't we better call Tricia? If it's Karen and John, we need all the facts we can get.'

'If it's them and strong enough to wake us up,' Moira said grimly, 'we need the Elders.'

Within a quarter of an hour they were all gathered in the kitchen, the warmest place in that early dawn; the High Priestesses and High Priests of all fourteen covens, Tricia Hayes their best clairvoyant and old Sally who had heard them moving about and had got up to stoke the fire and make them a hot drink. Dan and Moira had not had to rouse them all; Tricia herself and several of the others had also been wakened by the psychic shock-wave and were already getting dressed.

'Well, Tricia?' Moira asked. 'What can you tell us?'

'Blood,' Tricia said. 'That's what I got first. And tall stones – megaliths. Then I pulled myself together and tried to be calm – it wasn't easy, I'd been overwhelmed at first… It's the Angels of Lucifer.'

No one asked 'Are you sure?' because they knew Tricia. If she was not sure, she said so.

'Megaliths,' Dan said. 'Stonehenge and Avebury are both on their doorstep.'