She heard herself speaking, doing the one thing she had intended not to do: asking questions that were not for Anna, ‘Please, in what way does this composer seek my aid?’

The glass began to move even faster, 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.’

They looked at each other in fear and wonder.

‘This is crazy,’ said Jelly. ‘It talks in sentences?’

‘I want to stop,’ said Anna. ‘It’s too strange. Please, Jelly, can’t we put on the light now?’

‘Just one minute more? I’ve got to know who this is,’ Jelly pleaded. Clearly it was not Sep; she didn’t know whether to be sorry or thankful. ‘Perhaps it’s Onkel Jo.’

Adila was one of the last pupils of their great-uncle, Joseph Joachim, whom they and many others called ‘Onkel Jo’: the violinist who had been a close friend of Johannes Brahms, and of Robert and Clara Schumann. Joachim’s playing and teaching had shaped generations of musicians; he was a celebrated performer and strict, demanding instructor who had died when Jelly was 14. ‘And if it is… who could the composer be? For Onkel Jo – surely Brahms?’

They waited, fingertips poised on the glass. After a lengthy pause, it drifted through a 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 felt as if she had fallen head first into the sea and was trying to pull herself out, feet and hands slipping in all directions. This couldn’t be real.

‘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 continued. ‘May be museum,’ the transcript read.

‘I’m scared,’ Anna pleaded. ‘Aren’t you?’

Jelly was experiencing an inner clash of titans: a thick-skulled ogre of scepticism, aided by a Himalayan Yeti of fear, was wrestling against her musical self – which, at the notion of an unknown violin concerto by Schumann, had sparked into a burgeoning inferno of curiosity. This couldn’t be real – but what if it were? What would the piece be like? 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.