Nancy looked to the sky as she followed Violet and their grandfather out of Cupola House a little after nine o’clock that evening. The comet flashed brilliantly, suggesting the form of a glimmering woman with long flowing hair reaching for the stars. It was at its closest point to Earth, yet the air was fresh and sweet. The dire prophecies about the poisonous gas from the comet’s tail were false, just as most rational people had predicted.

Grandfather was dressed in the slightly too tight black suit Nancy had found in his wardrobe. Violet had dusted it off, while Nancy had used the ancient flat iron to remove creases from a shirt. They had both helped him attach the collar and cuffs to his shirt and fix the blue silk bow tie round his neck. Violet had pulled the summer dresses their mother had thought to bring from the carpet bag – cream muslin with lace collars and a blue sash for Nancy and a pink sash for Violet. As Nancy laced up her shoes, she had the sudden memory of Mother in her nightgown polishing them a few days before they left for Suffolk. Her throat constricted with worry for their mother alone in her cell.

“No matter what the outcome, we shall all look the picture of respectability tonight,” Grandfather said, his eyes glinting with intent as he looked at Nancy and Violet approvingly.

As they strode down Abbeygate Street past the fluttering flags and banners, Nancy noticed the windows above the haberdashery shop were dark; Burch and his parents must already be at the party. She felt a knot of fear and anticipation as they turned the corner at the bottom of the street to find Angel Hill thronging with horse carriages and motor cars that had brought people to the party. The men tending to the horses were busy shovelling up dung or standing in huddles admiring the night sky. Light from the tall Subscription Rooms windows puddled on the pavements, pulling them closer. People chattered excitedly as they queued up on the building’s balcony to look at the comet through the brass telescope. Nancy’s eyes were drawn upwards to the small copper-domed observatory on the roof. She thought of the money hidden under the floorboards and wished for the hundredth time Mr Cavendish would also do the right thing and stand up to the mayor.

Violet was staring at the pillared entrance to the Rooms, where a lady in a peacock-blue dress and her gentleman companion had been stopped by two suited doormen and were being asked to show their party tickets. “Oh,” Violet said in dismay.

“What is it?” asked Nancy.

“We don’t have tickets to the party. How will we get inside?” said Violet.

Nancy frowned. Her sister was right. They had overlooked a vital detail in their plan to confront the mayor.

“We are not buying tickets. I refuse to hand over good money only for it to be taken by that thief,” said their grandfather gruffly.

“There may be no need,” said Nancy, a plan forming in her head. “Burch is at the party. Perhaps we can tell the doormen we have an urgent message for him, and I could slip inside? He’ll be happy to help us.”

Grandfather frowned. “Hmm. That is not without risk. What if the mayor sees you?”

“I could do it,” said Violet, pulling on Nancy’s sleeve. “I’m smaller than you and good at hiding.”

Nancy shook her head. “No, Violet. It would not be safe.”

“Please,” said Violet, clasping her hands together and jiggling on the spot. “I want to help.”

Nancy and her grandfather exchanged a look. “She is small and nimble. It may be our best chance,” said Grandfather.

“I’m as angry as you at the mayor. You must let me help,” pleaded Violet. Nancy looked at her little sister’s steely jaw, her clenched fists and felt a burst of gratitude and pride. “All right. But you must be careful.”

Violet grinned. “Of course.”

“There is a tradesmen’s entrance to the building on the lane that runs alongside it,” said Grandfather, pointing it out. “If you can find Burch, see if he’ll take you to it. We’ll wait by the door, then you can let us in.”

“And don’t speak to anyone apart from Burch,” said Nancy, taking Violet’s hand and giving it a quick squeeze.

With the plan agreed, the three of them approached the front entrance and were greeted by a buzz of noise and activity from within. Through the open doors Nancy saw ladies in fine dresses of lapis, indigo, turquoise and cerulean blue, the sparkle of diamonds and rubies round necks. Gentlemen in dark suits sipped from champagne glasses, their heads tipped back as they joked and laughed. The air crackled with anticipation, like the static before a storm.

Two men were standing near the entrance having a smoke. “Did you hear what Sir Robert Ball of the Cambridge Observatory said about the comet?” said one to the other. “It is as likely that the Empire State Express train from New York to Chicago would run into the night mail train from London to Edinburgh, as the comet would collide head-on with Earth. To think people have even imagined such a thing!” The men roared with laughter. Everyone had pushed any fear of the comet to one side – they were prepared for a night of merriment instead.

The shorter of the two doormen, wearing top hat and tails, greeted them. “Good evening,” he said. “May I see your tickets, please?” He looked at Nancy’s grandfather a little harder, his cheeks suddenly tightening. “Mr Greenstone?” He exchanged an uncertain glance with the taller doorman.

Nancy sensed her grandfather stiffen by her side.

“I did not expect to see you here…” the taller doorman said haltingly. “Does the mayor know you are coming?”

Grandfather shook his head. “We are not attending the party. I need to get a message to Burch Cavendish – he is inside.”

The doormen looked at one another. “I’m afraid that won’t be possible,” said the shorter doorman. “Admission is by ticket only.”

“And all the tickets have been sold,” said the tall doorman.

“My granddaughter, she can take in a message. It is urgent,” said Grandfather. The doormen looked at each other again then shook their heads at the same time.

“I know your mother, don’t I?” said Grandfather, peering over the top of his spectacles at the tall doorman. “I remember her coming into my shop years ago for a remedy to help her rheumatism. If I recall rightly, the herbs I provided made her feel much improved.”

The doorman chewed on his bottom lip, his cheeks flushing.

“Please,” said Nancy, looking at Violet. “My sister can deliver the message and be in and out in a flash.”

“I’ll be ever so quick,” said Violet, giving them an innocent wide-eyed look.

The doormen conferred with one another again. “She’s just a girl. What harm can come of it?” said the taller one.

“I suppose you’re right,” said the smaller one, scratching his chin. “Go on then, in you go. You might find Burch helping in the bar upstairs. I saw him heading there a short while ago.”

Nancy held her breath as she watched Violet bolt through the entrance door and disappear into the throngs of people.

“Thank you,” said Grandfather, giving the doormen a nod. “We shall wait round the corner.” Nancy felt the eyes of the two doormen boring into their backs as they nipped round the corner and into the darkness of the lane.

“Violet’s inside!” exclaimed Grandfather, his voice bursting with pride. “I must say, it does feel good to be taking action. It makes me wonder why I have left it so long.”

They waited quietly in the shadows by the back door, hearing distant roars of laughter and the clink of glasses. Nancy thought people would not be having quite so much fun if they knew some of the hard-earned money they’d used to buy tickets was lining the mayor’s pockets, rather than the charity’s.

“Where is she?” asked Nancy after a while. She placed an ear to the door but was greeted by silence. At least five minutes had passed since Violet disappeared inside and she felt a rush of concern for her little sister.

“Have faith,” said Grandfather firmly. “I feel sure she will be all right.”

Nancy shuffled closer to her grandfather. She had known him for less than a week, yet was fond of him and took comfort from his words.

The sound of the door bolts being drawn back a few minutes later made Nancy jump. The door opened to reveal a small figure and a much taller one illuminated in a blade of light. Violet and Burch! Burch’s face was as puzzled as a question mark as he stood back and ushered them into a corridor which smelled strongly of steamed fish. Nancy peered at her friend in wonder. His green delivery overalls had been replaced with a grey suit and waistcoat, peach necktie and cream shirt, and his hair was neatly combed. He was a polished version of the boy she had grown to like and admire, a boy who liked learning about science and the stars and went to great lengths to help those in need.

Burch looked at the three of them expectantly. “Mr Greenstone, what are you doing here? Violet found me; she said you needed my help.”

“I’ve told Grandfather everything. We’re going to confront the mayor,” said Nancy.

Burch’s face was a combination of awe and fear. “But what about the threats the mayor made in the observatory this morning? What’ll he do to my pa?”

“We’ll keep your pa out of it, Burch,” said Nancy’s grandfather, placing a hand on Burch’s shoulder. “He has made his decision to hide the truth and there is nothing we can do about that. But Nancy and Violet have made me realize that it is time the Greenstone family stood up for what is right. I will not cower away any longer with people believing the lies the mayor tells about me and my family. It is time to speak up.”

Burch whistled through his teeth. “Gosh, Mr Greenstone. I’ve never heard you speak like this before.”

There was a cough to their left a little way along the corridor. Nancy turned to see Mr Cavendish’s taut cheeks, even paler than usual against his smart dark suit. “Your ma asked me to find you. The mayor’s presentation is about to begin,” he said to Burch, approaching the four of them warily.

“Hello, Mr Cavendish,” said Grandfather in a kind voice, pushing his spectacles onto his nose and blinking.

A flush rose above the collar of Mr Cavendish’s necktie. He pulled at it, as if it was too tight. “I heard what you said just now, that you’ve come to speak up. That’s…brave of you.”

Mr Greenstone grimaced. “It is not bravery, Mr Cavendish. It is a determination to ensure the truth is told. Whether people choose to believe it will be up to them.”

Mr Cavendish fiddled with his cufflinks; his mouth twisted in misery. “In my book telling the truth takes courage, which is something I’m severely lacking.” He glanced at Burch. “I know you’ve a low opinion of me, but I feel trapped by the mayor, on the edge of a precipice.”

Burch placed a hand on his father’s arm. “Then perhaps it’s time to take a leap like Mr Greenstone. Whatever happens, Pa, I’ll stand by you.”

Mr Cavendish placed a hand over his son’s. His stooped shoulders were quivering, just as they had been in the observatory earlier that morning. But instead of staring at the floor and his shoes, he was looking Burch directly in the eyes. “I’ve wondered many times what would happen if I took control of matters and spoke up about the mayor. Perhaps I was asking myself the wrong question.”

“What do you mean?” asked Burch.

Mr Cavendish’s Adam’s apple bobbed in his throat. “I should’ve thought about what would happen if I didn’t stand up to the mayor – and the answer’s a life under his thumb, and I can’t bear any more of that.”

A slow dawn was rising in Burch’s eyes. “You’ll speak up too then, tell the truth?”

Mr Cavendish gave Mr Greenstone and the children a small and shaky smile. “Mayor Douglas’s actions have throttled me for far too long. I need to cut the noose, no matter what the outcome.”

“Yes,” hissed Violet.

Mr Cavendish looked at her and smiled softly, shaking his head a little. “These children have taught us a thing or two about standing up for the truth.”

“Indeed,” said their grandfather, patting Mr Cavendish on the back. “We are stronger in numbers, Mr Cavendish. I am proud of your decision and I will stand by you too, no matter what happens this evening.”

“We need to go,” said Nancy, hearing voices at the end of the corridor.

“Yes, folks were already gathering in the ballroom when I came looking for Burch,” said Mr Cavendish. He turned to Burch and Violet. “If I’m going to speak up, I need to do it well. Would the two of you be able to help me with something?”

“Of course,” said Violet.

“Absolutely,” said Burch with a grin.

“Good,” said Mr Cavendish. His shoulders seemed to be lengthening and straightening before Nancy’s eyes now he had decided to take action. “Two beats of the gong will announce the mayor’s presentation of the charity cheque from the balcony,” he said. “The mayor will come up the main stairs to make a grand entrance, so it will be safe to wait in the corridor that adjoins the balcony. I’ll be as quick as I can with Violet and Burch.”

A combination of nerves and excitement knotted Nancy’s stomach. She thought of her father representing clients in court, how he’d told her that in his early days he had to fight his nerves by pushing all other thoughts from his head and focusing on the message he needed to deliver. Nancy’s message was clear as a bell in her mind. This was about telling the truth and clearing Mother’s and Agatha’s names. But how would the mayor and the people of the town react to hearing what they had to say? Would they be booed and hissed from the ballroom? Would the mayor have them ushered away by the police? A loud boom vibrated in Nancy’s ears. It was the first gong! The mayor’s speech was about to begin.