My name is Irene. I’m seventy-three and I clean the Halloran Ballet Academy every evening after the last class. For nine years I have swept the same studio floor, and not once have I said that I could dance.

That Thursday the new principal dancer, Adrian, was rehearsing with the company. Every magazine called him the finest dancer of his generation. When he noticed me standing at the back with my bucket, he stopped mid-phrase and turned toward me.

‘Ma’am, rehearsal is closed. We don’t need an audience of people who only mop floors.’

The dancers behind him giggled. One of the girls hid her smile behind her hand.

I looked at him for a long moment. Then I leaned my mop against the barre, took off my apron, and slowly lifted both arms, the way I had not done in forty years.

The room went so still that I could hear the studio clock.

My feet remembered before I did. The first position. The second. The port de bras that my teacher in Leningrad had drilled into me at ten, and the arabesque that had once made a great choreographer shed a tear.

I did not perform. I simply began to move, and in ninety seconds I had shown them everything Adrian had been trying to find in the studio for a month.

When I finished, nobody clapped. Adrian had gone white.

‘That is the variation from Serafina,’ he said hoarsely. ‘It was lost after the war. Only one dancer ever performed it.’

‘Irina Volkova,’ I said. ‘That was my name.’

I had left the stage at thirty-three after an injury, and left the country the same year, and I had become a woman nobody looked at twice. I never told anyone.

Adrian dropped to one knee. Not in mockery. He took my hand and said, ‘I have spent my whole career trying to dance your ballet. Will you teach me?’

I taught that company for three months. On opening night Adrian danced Serafina, and when the curtain fell he walked into the wings, took my hand and led me out onto the stage for the bow.