Truthful did not dance the first dances, because Charles was busy assisting the Marquis, or rather in encouraging him to leave his throne and his waves to join his wife in greeting the guests. Then he walked around and took part in what was hoped to be surreptitious conferences with various Viking footmen. But he returned to Truthful for the first waltz, and took her in his arms as the music began. They danced in silence for the first few bars, Truthful counting her steps until she relaxed in the knowledge that she did know the dance, and Charles would successfully lead her anyway.

“Any sign?” she asked softly, as they twirled near the deserted Canute’s throne.

“No,” replied Charles worriedly. “We’re up to six mermaids arrested now, but none of them are her. It may be as well she doesn’t turn up after all. Sir Everard says the Emerald is definitely Canute’s Valdbjarg. Or rather, his wife Aelfgifu’s Valdbjarg.”

“What does that mean?” asked Truthful.

“Sir Everard says the closest he can make it is ‘power-stone’,” said Charles. He was looking over her head, eyes flickering about the crowd. “Which does not sound at all as if the only thing it can do is make or quell storms.”

As he spoke, the music suddenly faltered, with the shriek of a violin bowed wrong. Charles instantly swung Truthful to the wall and they turned together to look up at the musician’s gallery.

A tall, striking-looking man in the ordinary rather drab evening clothes of a working musician let his violin fall, stood up from the seated musicians and moved to the railing of the gallery. The conductor there gestured violently with his baton.

“You! Take your seat at—”

He never finished. The tall man plucked open his coat and tore away his neck-cloth, and the ballroom was suddenly filled with an eldritch green light that emanated from the brilliant emerald he wore on a silver chain about his throat.

As the light spread, all movement stopped. Truthful felt the power that came with it grip her every muscle. Her hand, already to her shoulder, reaching for an arrow, was held motionless. She saw Charles’s fingers caught at the opening in his tunic, no doubt reaching for a pocket pistol he could not remove or point.

“Welcome to my masquerade!” declaimed the man, but it was not a male voice. It was higher and piercing: the cold, heartless voice of Lady Amelia Plathenden. “Do not fret! I shall not keep you long. And when we go, we shall all go together. Yes, all of you, who would not grace my parties, who cut me in the street, who would not grant me vouchers to Almack’s! Who killed my husband! Even the fat prince, thinking himself safe in his dwarfish palace. He will go with me too. You will all go with me.”

A chill breeze came with her words, making the candles flicker in the candelabras high above, and the music in the stands blow off the stands and scatter down like leaves, the only movement in the silent, motionless ballroom.

But it was not the breeze that chilled Truthful’s heart. The breeze was only a small harbinger of what Lady Plathenden had truly wrought. Truthful could feel it through her bones, sense it building to the south. For now, it was far off, gathering size and strength. But all too soon it would begin to move.

Lady Plathenden was using the Emerald to conjure a giant wave.

A wave that would come crashing down upon Brighton. A vast wall of swift water, towering higher than the clouds, it would demolish the grand houses on the Marine Parade, the humble fisherman’s cottages to the west, the shops and dwellings in the narrow lanes.

The great wave would smash the Assembly rooms of the Old Ship to pieces and sweep the Marine Pavilion away, iron framework and all.

As Lady Plathenden said, they would indeed all go together.

Everyone, from the Prince Regent to the humblest fish-wife.

All would be killed.

Truthful thought of Charles, and his fear of drowning, and resolved that it would not be so. She looked up at Lady Plathenden and saw her outline shiver. In the green light of the Emerald she looked less and less like a man and more like a woman uncomfortably in male clothes. Truthful narrowed her eyes and concentrated on the Emerald.

You should not be doing Lady Plathenden’s bidding, Truthful thought fiercely. You should be doing mine! Let me move, for you are my Emerald, as you were my mother’s, and my grandmother’s, and so many mothers and grandmothers before them, back to Aelfgifu and beyond. You are mine to command!

“What?” asked Lady Plathenden, apparently of the empty air. She looked down, searching for Truthful. Her head moved from side to side as she gazed into the crowded dance floor, a sea of statues, of popes and kings and queens and gods and goddesses. All masked, disguised, unable to be identified.

Truthful felt a warmth in her fingers, a tingling in her arms, and knew that she could move again. She no sooner felt it than she did so, drawing an arrow from her quiver with one swift motion, setting it to her bow and drawing the bowstring back.

The movement caught Lady Plathenden’s attention. She reached for the bone wand, smoke already trailing from her fingers, a spell begun.

But it was not completed.

Truthful’s arrow sped true, sprouting shockingly from Lady Plathenden’s eye, the azure fletching no longer the only piece of colour, a sudden scarlet spreading down the shaft. The glamour left her, the bone wand fell from her nerveless hand, and she toppled over the railing to crash into the floor below, between a unicorn and an unlikely cloth-of-gold clad milk-maid.

The green light winked out as if it had never been. Truthful ran to the body before anybody else could begin to move. Snatching the Emerald, she broke the silver chain and ran for the door.

“Go to high ground!” she shouted. “She has conjured a giant wave!”

Lady Plathenden might be dead, but the wave lived on. Truthful could feel it, and knew it to be moving now. It was already more than a hundred feet high, and two miles wide, and it would strike the coast in less than fifteen minutes.

She ran down the stairs, jumping three at a time. Startled Vikings clutched their axes and made slow movements as she passed.

“Get everyone to high ground!” shouted Truthful, again and again. “High ground!”

Outside, she saw her cousins and the real Major Harnett, but did not pause. They rushed to her, but she did not answer their questions, merely shouting as she ran past them towards the beach.

“High ground! Plathenden called a great wave! Go to high ground!”

It was much darker across the road, away from all the lanterns and flambeaux outside the Old Ship. There were also fishing nets spread out to dry, causing Truthful to stumble and hop and almost fall. She was regaining her balance when a hand steadied her, and she cried out.

“What must you do?” asked Charles tersely. “Get to the sea?”

“Yes!”

“This way, between the nets!”

They ran hand in hand, feet sliding in the pebbles. But the sea was not where it had been, not where Truthful expected. It had drawn back, several hundred yards at least, exposing a great expanse of wet pebbly beach, dark in the night.

“Go back, Charles!” she begged. “Run for the hill. Even if I get to the sea in time, I don’t know if I can turn the wave!”

Charles did not answer and he didn’t let go her hand. They ran on together, and as they ran, the crescent moon came out from behind a cloud, making the wet beach a silver road.

In the moonlight, they also saw the wave. It looked like a great, dark storm gathering on the horizon, but they both knew better. Splashing and slipping, they threw themselves forward, Truthful casting away the bow that she didn’t even realise she’d still been holding all that time.

At last, they plunged into the sea itself, too vigorously, both going under and coming back up spluttering.

“Hold me,” ordered Truthful, bracing her feet against the small waves that sought to push her over. Charles stood behind her, leaning forward, his hands around her waist.

Truthful raised the Emerald, looked into it, and bent all her will on turning back the vast wave that filled the sky.

Chapter Twenty-Two

Completely and Thoroughly Compromised

Green light fell from Truthful’s fingers, brighter than the moon. The waves that had threatened to bowl her over quietened, and the sea in front of her grew still. Slowly this spread, till the crash of surf all but disappeared, replaced by the softest lapping of the sea on stones.

“I can’t turn it,” whispered Truthful. “It is too strong.”

Charles’s arms tightened around her, and he kissed the top of her left ear.

“Perhaps it is too much to ask that you save my life three times,” he said softly. “May I say I love you before we drown?”

“I can’t turn it,” said Truthful, ignoring this remark. “But perhaps . . . I have made it smaller . . . what was that?”

“I love you,” said Charles. “I just wanted to say it.”

“I love you too, idiot,” replied Truthful affectionately. She lowered the Emerald, but the green light didn’t fade, and the immediate sea remained calm. “I think I have done all I can. We don’t need to stay here and we certainly don’t need to drown.”

“What?” exclaimed Charles. He looked across the moonlit sea. There was no longer an awful, horizon-spanning darkness. But there was a very large hump upon the water, a hump that was growing closer by the second.

Truthful was looking back up the beach. She vaguely remembered some structure, standing tall, closer than the houses on the Parade. A pump-house for the seawater cure, the guidebook had said . . .