Ada’s hand closed over her father’s letter still in her pocket. Not yet. She wasn’t ready to read it yet.

The orchestra drew to a single, piercing note. The players took the stage, and then the score swelled into the opening bars. Ada’s breath caught in her throat at the spectacle, despite herself. The stage was split horizontally into two levels, so two scenes could be shown to the audience at once. It was like floors of a house, decorated to the taste of a middle-class merchant or lawyer. It looked the same as their house in the Marais district when she had still lived with her father. Paintings hung on the walls of the parlour with a rococo mirror above the fireplace and second-hand harpsichord in the corner. Two men stood at the table, examining plans spread before them. On the second tier, the space was set up as a bedroom, complete with four-poster and a zinc bathtub ready for use. Scandalously, a woman was in the tub being attended to by her maid.

The first scene had only just begun when Ada saw a wisp of smoke curling from the backdrop. It thickened, growing grey-black, and then at once like a lightning flash, a large orange flame licked through the fabric, jumping to the second tier of the stage, lapping around the lathe and plaster walls.

For a beat, the audience was stunned, as though no one could understand what was happening in front of them. Someone applauded.

Then chaos erupted. The crowd surged to the back where Ada and Al were standing. People were screaming and pushing each other out of the way. The pit was a heaving tide of faces and wigs and hair merging and scattering like a school of fish. Ada saw several people disappear underfoot before she could move. Al grabbed her arm and held on tight.

‘Let the horde go past,’ he said, eyes darting. ‘I’m not being trampled to death in a third-rate venue like this.’

She flattened herself out of the way. Above them the balcony shook from hundreds of stampeding feet. Onstage, the fire spread quickly to the portraits in the parlour, alighting its fingers on the back of the settle. It was speeding across the set like rats on a corpse, curling flakes of paint off the walls, frothing over the upholstery. The heat was like an amazing inferno.

The initial mass of people pushing towards the exits had stopped. Now they were bunched, clamouring and yelling, pressing forwards – but going nowhere. Al met Ada’s eye.

‘Well, that’s not good.’