But Alisha was nodding, and she moved off among the people without looking back. Not knowing whether he should, Roger followed.

Passing beneath a golden archway, he took a free glass of warm wine from a table and sipped as he walked. Real food would be better, but he did not want to lose Alisha. Nor did he want to interrupt her. He walked on, past flowsteel helical ramps leading to a temporary piazza on stilts where hundreds of revellers were dancing, the music a complex rock-baroque symphony that suddenly went discordant with an underlying da, da-dum, da-da-da-dum, da-da.

But the stamping feet of dancers continued, as if only he could hear the new theme.

He was among revellers who were dressed in beautifully expensive silk clothes, real fabric rather than smartmaterial, some with masks made from synthetic feathers, others with holomasks, rendering animal snouts and eyes with exquisite exactness. He bumped into one by accident - a man wearing a canine head and Egyptian robes: dressed as Horus or Osiris, or whatever - and apologized. It had distracted him, and for a few seconds he had no idea where she was, but then he saw.

Alisha was talking to a Luculenta.

The woman was tall, dressed in black and silver. No wonder Alisha had ignored her friends; even from here, in a crowd of thousands, Roger could sense the woman’s charisma.

All around was distraction: holoflames and fireworks, a thousand illuminations and—

There. Darkness, moving in impossible ways. Then gone.

I’m hallucinating.

But it seemed he was not. Just for a moment, in a gap between revellers, he spotted a pale-faced woman he knew for certain - Dr Helsen - and beside her a stocky man, who might be the friend he had seen her with before. Then the crowd moved like one massive creature, shifting position, hiding Helsen and the other man from view.

Alisha was leaving the plaza, walking with the Luculenta. Roger was tired and going crazy, so the sensible thing would be to find food and a place to sit down, maybe sleep. But his feet moved by themselves, and he continued to follow.

In this crowd, no one would notice his behaviour.

The reveller dressed as Anubis took an ice-cream from a vendor. As he licked it, the cone seemed to disappear inside his jackal’s head, the Horus holomask. After a moment, he made a gesture, and the mask faded.

Now he could eat his ice-cream more naturally. As he did so, he watched two pairs of figures leave the plaza in opposite directions: Helsen and Ranulph one way, the Spalding girl and Rafaella Stargonier in the other. Young Roger Blackstone chose to follow the latter.

The question for Superintendent Keinosuke Sunadomari was, who should he be watching?

TWENTY-EIGHT

EARTH, 777 AD

From the camp came the sound of drumming and the cheers of dancing warriors. Tall carved poles were hung with shields. Orange light blazed from massive fires. For a temporary location, there was a lot of organization involved in setting up this place.

There was no point in asking whether anyone else heard disturbing music among the drums - Ulfr knew it was only him. His mood disquieted Brandr, the warhound occasionally growling.

It was not just that Ulfr felt no sense of celebration, either at the troll’s defeat or at the way several dozen chieftains had managed to come together in peace. For he was used to slipping in and out of dreamworld, often guided by sweet Eira back home. Since Heithrún had led him into trance the previous night, strange dreams kept recurring: of himself among warriors whose bodies did not appear like normal flesh, looking more like the crystal that topped Heithrún’s staff, with which he had driven the troll’s spirit out of its stony body.

‘If they are elves of the light,’ he said to the hound, ‘then we could do with their presence. For we have an elf of the dark among us.’

Brandr growled at the mention of Stígr. They had spent all day hunting, mostly to be alone, away from the poet’s growing tale of the travellers’ battle against the troll - the battle that, as far as Ulfr could tell, Stígr had observed while cowering beneath his cloak, tucked face-down behind a small outcrop.

During the hunt, Ulfr had surprised a young fawn who had strayed from her mother. She was within an easy spear’s throw, and Ulfr was downwind; but her legs were slender and fragile, and her big dark eyes - when she finally saw him - held a surprised awareness that reminded him of Jarl. In earlier life, not meeting his end bound to a doorpost, cut apart by axes and hammers.

‘You should grow older,’ Ulfr had said, ‘and make deerlings of your own, before sacrificing yourself to men.’

The fawn had skittered, then galloped away.

After a moment, he pulled himself out of memory. The drumming had stopped at some point, and the only sounds were the crackling of fires and a lone voice, speaking.

There was a hillock to one side of the camp’s centre, and two figures stood on it. The man speaking was Gulbrandr, chief of the party that Stígr had travelled with. The other figure, wide hat low over his face, was Stígr himself.

Were Stígr’s lips moving? From this distance, and because of the shapeless hat, it was hard to tell. Besides, it was Chief Gulbrandr whose words boomed across the warriors, and everyone’s attention was on him.

And on the misty visions growing in the air above them.

Sorcery!

Could no one else see it?

‘By Mjǫlnir, they are ensorcelled.’

Brandr was silent, a warhound ready to attack.

‘—to south and west and east,’ Gulbrandr was saying, ‘where the folk are rich and soft, no longer warriors. Their ancestors’ strength is gone.’

Ulfr was not sure of that. But the entranced warriors had no doubts.

‘A-viking, a-viking,’ they chanted. ‘A-viking! A-viking!’

Their dreams were visible above their heads: the glory of battle, golden spoils, and Valkyrie, the soul-choosers, swooping down to fetch the shades of the slain.

It was real; and it was wrong: turning honourable courage to something dark. But there were so many warriors between him and the two men on the hillock.

‘We take from the weak,’ roared Gulbrandr.

‘A-viking! A-viking!’

‘We take from the cowards.’

‘A-viking! A-viking!’

‘We take their women and their gold!’

‘A-viking! A—’

Ulfr grabbed a warrior’s head and twisted.

‘—viking!’

‘Because together we are greater—’

He forced another two men aside, used his elbow, kicked another in the back of the knee, creating space.

‘—than those who hide inside—’

Brandr bit a man on the calf, allowing Ulfr to push past.

‘—city walls like rats!’

A huge warrior swung at Ulfr but he moved inside, cycling punches and slaps to knock the man down, and then he was into a clear space. Gulbrandr’s eyes widened. The nearer warriors grew silent, though the others continued to chant.

‘A-viking! A-viking!’

Twisting curtains of black light fell on him, but he was faster, sprinting across the gap, leaping high - stay back! - as ravens from nowhere clawed at his eyes, but too late - bastards - and his elbow smacked into Gulbrandr’s forehead, splitting the skin.

But he was not aiming to put the chief down - he was going through him. Stígr’s arms were raised high, about to call down some dark magic, but Ulfr’s kick scythed across his legs, he hammered with the side of his fist, then Stígr was down.

Ulfr dropped knees-first on to Stígr’s chest, feeling the crunch of ribs breaking; but the man was already unconscious, and the dream-images overhead were evaporating. The ravens screamed, wheeled through the air, and were gone.