Isla had completely forgotten about it in the emotion of the afternoon. She put down her tea, pulled her handbag towards her, across the carpet, and found the mysterious letter inside.

The envelope was obviously old. It had a red and blue stamp on its right hand corner and an address written in thick black strokes: Miss Edith Anstey, Rose Cottage, Steeple Hill, Heaven’s Cove, Devonshire, England.

Edith had the same surname as their grandmother, before Jessie had married Arthur – the love of her life who’d died when Isla and Caitlin were small children. Caitlin remembered him but Isla had been too young to lay down memories of the man who was smiling at them now from a photograph on the windowsill.

‘What does it say?’ urged Caitlin, pulling her cardigan tightly around her as if she was cold.

Isla pulled out a folded sheet of paper and opened it. She admired the rounded, dark strokes of a fountain pen: the same thick strokes as in the address.

‘So?’ urged Caitlin impatiently. ‘What’s in this mysterious letter?’

Isla cleared her throat and read it out loud:

March 20th 1919

My dearest Edith,

My plans are made at last! I arrive into Southampton on RMS Sylvestria on April18th and will travel immediately to join you in Heaven’s Cove. Our return passage is booked for midday, exactly one week following, and we are due to dock in New York late in the evening of May2nd.From there, you, I and my grandmother will travel on to our new life in Florida.

I will not write more now because there is much to be organised. But know that my heart is full at the thought of seeing you again, my beloved girl. I cannot wait to bring you home and make you my wife. I am counting the days until we are together again, and I remain forever yours,

William

Isla stopped reading, feeling choked with emotion. She was a big softie when it came to romance. She re-read the words penned by William, who had crossed the Atlantic one hundred years ago to make the woman he loved his wife. What had happened to them? she wondered. Were their lives together happy ever after?

Her thoughts were interrupted by Caitlin, who’d come to stand nearby and was craning over her shoulder at the letter.

‘Who the hell was Edith?’ she asked.

‘I have no idea but I imagine we’re related to her in some way. What are you doing?’

‘I’m looking Edith Anstey up on the internet,’ said Caitlin, jabbing at her phone screen. She scrolled through the information that came up and shook her head. ‘Nope. Nothing comes up immediately that might relate to her. What’s William’s surname?’

‘I don’t know. He’s just signed it “William”, though…’ Isla picked up the envelope, turned it over and smiled. ‘He’s put his return address on the back. It says William Columbus, 132W125thStreet, New York.’

Caitlin did another quick search on her phone and puffed air through her lips. ‘Nope. That’s a dead end too.’ She peered at her screen. ‘Looks like he lived in Harlem. Harlem’s a fascinating place. I read that it takes its name from a city in the Netherlands.’

‘Whatever,’ said Isla, riled by Caitlin’s propensity to be easily distracted. ‘But is it definitely a dead end?’

Caitlin puffed out her cheeks. ‘Who knows? But I can’t see anything about a William Columbus. He’d have died a long time ago.’

‘I guess so,’ said Isla, feeling disappointed by the lack of instant information and desperately wanting to know more about Edith’s move to America.

She suddenly had a mental image of New York, one hundred years ago, with the Roaring Twenties about to begin: the sounds and smells; the buzz and excitement of the big city. And she had a flash of yearning for how her own life might have been, if things had been different.

‘So that’s it, is it?’ Caitlin reached over her shoulder, took the letter and scanned through it. ‘It’s all very sweet – a heartfelt letter to someone who’s probably distantly related to us. But why did Gran leave it to us in her will? We’d have come across it when we were clearing out the house.’

‘I expect we would, but we might not have given it enough attention. Not if we didn’t know it was special in some way.’

‘But in what way is it special?’ Caitlin shook the piece of paper, as if she was hoping the answers would fall from it. ‘At the end of the day, it’s just an old love letter from a man who’s coming to collect his fiancée so they can start their new life together. With his grandmother in tow, which isn’t the most romantic of prospects.’

Isla shrugged and, on a hunch, turned the envelope upside down. A piece of paper dropped out and fluttered to the carpet. When she picked it up, Jessie’s familiar spidery handwriting made Isla’s stomach flip.

‘It’s from Gran,’ she said, her throat tight. ‘It says: Don’t get in a spin, girls, though mistakes can cost you dear. This one brings good fortune and, I hope, will make you cheer.’

‘You what?’ Caitlin raised one of her perfectly plucked eyebrows.

‘It’s a riddle,’ said Isla, bittersweet emotion rushing through her. ‘A riddle from Gran.’