Jelly laid out the letters alphabetically in a two-row semi-circle on the kitchen table – which seemed the least formal, least frightening environment. Beside them she set in place an upended tumbler. In his basket by the back door, Cesar yawned and thumped his tail before going back to sleep, nose on paws.

She scrawled “yes” and “no” on pieces of paper ripped from a notebook, each in her huge, untutored hand. She had gone to school for eight days; each time, she’d cried so much that eventually her mother could stand it no longer, took pity and kept her home. After that, Jelly could – and did – play her violin to her heart’s content. Today she fitted about twelve words on to an average piece of letter paper.

They lit a sole candle; around it the rest of the room disappeared into the night, while an island of surreal creamy gold highlighted the whorls in the old wooden surface. Now this seemed a cavern fit for other-worldly activities. The two women sat opposite each other; Jelly tried to steady her hand, which was quivering a little with nerves.

“Ready, darling?” she said, to reassure herself more than Anna. “So, let’s sit quietly and clear our minds...”

They waited, each with one finger upon the glass, silent, focusing. The candle flame flickered in Jelly’s exhalations.

“Do we need to invoke something?” Anna whispered.

Jelly thought of Mary Southern's opening invitation. “Hello, is there anyone of friendly intent who would like to talk to us?”

Twenty seconds more went by in stillness. Maybe it wasn’t going to work? Then, beneath her fingertip, Jelly felt a slip of energy, like the prickle of an electric current.

The glass gave an unmistakable shift. Jelly and Anna breathed and waited. It moved, first left, then right – and was still.

Anna took a deep breath. “Is Mrs Adrienne d’Arányi there, please?”

“Darling, don’t ask for my Mamma. It’s not a telephone...”

Jelly was becoming aware of heat gathering in the centre of her palms – a concentration of some intensity, first a superficial tingling, then gradually digging deeper and deeper. Soon her hands seemed to be pierced through with a thousand pins, and around the central heat spots, numbness began to spread through her fingers and the muscles at the side of her palms. Before she could say anything, let alone make a break for safety, the glass started to glide along the table.

It circled the gamut of letters once, twice, and yet again; then swerved towards the letter G and on to its next choice, apparently galvanised by a propulsive force that Jelly knew was not hers and, to judge from Anna’s wide eyes, could scarcely belong to her either. Anna, left forefinger on the tumbler, noted down letter after letter. Jelly, paralysed with anxiety, was wondering what was happening to her hands. Wasn’t this what occurred when someone received stigmata? Yet there was no sign of blood – only the bizarre impression that someone had plugged electrodes into her palms and was charging them with energy beyond any semblance of her control.

In due course they derived from the glass’s motion one simple phrase.

“Oh no.” Jelly’s innards contracted further. “ ‘Glad to see you’ is almost what it said last time.”

“Is that Jelly’s mother?”

The glass slid towards ‘no’. Then, before either of them could speak to ask a question, it plunged onwards, letter by agonising letter, forcing their concentration.

Anna noted the sequence down. “This is a little strange.”

The glass slowed and ceased its motion, leaving them to read back the transcript - once, twice...five times.

“No?” Jelly stared into Anna’s eyes, feeling winded.

“I’m not seeing things,” Anna said. “Are you reading this the same way?”

“Does it say what it seems to?” The closest approximation to the letters the glass had delivered appeared to be: ‘A composer seeks your aid’.”

Anna was moistening her lips; through the active glass Jelly could feel her trembling. Part of her wanted to switch on the light and declare all of this, in best Donald Tovey fashion, nuff and stonsense.

Another part of her, though, did not. “What an odd thing for a spirit messenger to communicate to a violinist…” The pressure in her palms was almost painful. She thought she could make out, in the candlelight, a pink spot in the centre of her free hand, as if she had held it over a flame for a moment too long.

She took a breath and heard herself speaking, doing the one thing she had vowed to herself not to do. Do not talk to the dead. Do not ask for advice. Only for Anna. Not herself. Not – “Please, tell us something more? In what way does this composer seek my aid?”

The glass began to shift as fast as it might for Adila. It was many long minutes before it finally came to rest.

“He left the earth before you were born,” Anna read out. “He would like you to find a piece and play it. It has not been played for many years.”

“This is ridiculous. It talks in sentences?”

“Not exactly, but it looks to me as if that’s what these letters say...” Anna showed her.

“Yes... but who is it? Do you think this is Onkel Jo talking to us?” Jelly felt as if she had fallen head first into the sea and was trying to pull herself out, breath stifled, heartbeat out of control, feet and hands slipping in all directions at once. “And if it is...who could the composer be? For Onkel Jo – surely Brahms?” This year was Brahms’s centenary; he and Joachim had been close friends; it would make sense, assuming any of this made sense at all. They waited. After a lengthy pause, the glass drifted through the golden patch of light towards the R.

The name built slowly, letter by letter.

In front of their eyes two words were forming: ROBERT SCHUMANN.

Jelly slid, flailing inwardly, further into the ocean. This couldn’t be real. Someone was playing a joke on them. Or else Anna must be playing a joke on her. What a clever idea of hers. How on earth had she thought of it?

“Concerto,” spelled the glass, a step at a time. “D minor.”

“Jelly,” Anna said, “you're playing a practical joke on me.”

“But no, you are playing one on me.”

The motion under their fingers showed no sign of stopping. “May be museum.”

“I’m scared,” Anna pleaded. “Aren’t you, Jelly?”

Jelly was experiencing an inner clash of titans: a thick-skulled ogre of scepticism, aided by a Himalayan Yeti of fright, were wrestling against her musical self – which, at the notion of an unknown violin concerto by Schumann, had sparked into a burgeoning inferno of curiosity. There was no Schumann violin concerto; given Onkel Jo’s friendship with him, she had always wondered why not. Any other composer who knew Joachim would write a concerto for him to play; why not Schumann? This couldn’t be real – but what if it were? What would the piece be like? It made so much sense. She couldn’t turn away from that suggestion. She had to know more. “Hello?” she burst out. “Are you still there? Is it – this concerto – is it any good?”

What a question to ask a spirit messenger. It wouldn’t reply to such insolence. But that inexorable motion was beginning again. The letters kept flowing, as if pouring out of the glass, as if the visiting spirit, now that it had acquired this peculiar access to life, was determined not to relinquish it.

“‘It is not my best work,’” Anna read out the transcript. “‘But it is better than much music being written today…’” She shoved back her chair, clattered to her feet and plunged for the light switch. “Jeje, no! Help! That was Schumann! That was Schumann himself! I can’t do this! We have to stop. I’ve never been so terrified in all my life.”

“It’s all right.” Jelly’s whole body felt icy except for the hot spots in her palms, as if all her blood had rushed to them and formed whirlpools there. Electric light swamped the candle; the spell cracked and fell away.

In the brightness they blinked, steadied their breathing and clasped hands; Anna’s were cold and shivering. Jelly warmed them, rubbing hard. Her head had begun to throb with pain and exhaustion. It was nearly 2am. They sat without speaking, trying to absorb at least some small measure of what had just happened to them.

After Anna had gone home, Jelly, alone in the kitchen but for the slumbering Cesar, stared at the letters, the tumbler and the transcript lying where they’d left them. Her hands had cooled, her head cleared. What idiocy was this? She hadn’t pushed the glass. Anna was so frightened that she couldn’t have either. There had to be a rational explanation.

If this piece of insanity was to be believed, she had received a message from the spirit of Robert Schumann, or his…representative? Telling her that a violin concerto he had written was lying unplayed somewhere, and he wanted her to save it. Astonishing – an extraordinary demand, an overwhelming responsibility – that Schumann should choose her? But supposing it was a trick of some kind, a deception, or worse? If something truly supernatural had taken place, how could she be sure this communication was from a benevolent spirit and not a demon?

Adila, of course, would believe every letter of it. What on earth would she say when she heard? If she heard?

She could wait for Adila to come home, then tell her everything. Or she could clear away the evidence and pretend nothing had ever happened. It had to be nonsense. The very idea of a concerto by Schumann having lain unplayed all these years was ridiculous; if such a thing existed, every violinist in the world would want to play it, wouldn’t they? Besides, she’d lose face if she admitted that she had been indulging in the Glass Game, since she habitually poured scorn on Adila and Erik for it.

Jelly read back the transcript one last time – then took it upstairs to stow at the bottom of a drawer in Anna’s desk, in case it might someday come in handy. She’d leave it there, forget about it and tell her sister nothing now, nothing ever.

But while the clock ticked, while Alec slumbered, oblivious, in the bedroom and Cesar gave canine snores in his basket, and while around 3am the engine and brakes of a cab signalled that Adila was home, Jelly lay awake, still electrified, her hands throbbing. If Onkel Jo and his friend Robert Schumann could be there, communicating, then so could Bach and Beethoven, so could Shakespeare, Plato, Cicero, Aristophanes, so could Napoleon and the Duke of Wellington, so could her mother and Sep and...

It was too intangible, too confusing, too alarming. And yet... A violin concerto by Schumann? What if it were real? A work that was never played and about which nobody knew, for whatever reason? What would it be like? A piece by Schumann, the most beautiful, emotional, startling and impassioned of all the romantic composers, even if he were plagued by mental illness – how bad could that be? How could it have vanished? What if it really were there, waiting to be found, waiting for her, his friend Joachim’s great-niece, to find it – yet she did nothing? Supposing she ignored the messages, dismissing them as mere folly or the product of her own wishful thinking – and then the work turned up after all? But how to start looking for it? Supposing she were to find it and perform it? Supposing she could rescue it, save it from oblivion and infuse it with renewed life?