We looked at each other that first morning and smiled and it was as if we knew it straight away: we were a team. When the boys pulled on my tie, when they laughed at Max’s ankles sticking out of the bottom of his trousers, when the girls made fun of Elsa’s fancy ribbons – none of it mattered because we had each other.

‘If you’re the king, I’ll be queen,’ Elsa said now.

‘What about me?’ I asked. ‘It is my birthday, after all.’

‘We can have two kings!’ Elsa replied. That was so like her. Always wanting to be fair to everyone.

‘If you’re the queen, that means you have to marry one of us,’ Max said. ‘So who will you choose?’ He gave Elsa a look as he spoke. A look that I’d seen between them sometimes recently. I always pretended I hadn’t noticed. It felt like a secret they shared. A promise that excluded me. I told myself I was imagining it. They would never exclude me. Nothing would ever come between the three of us.

Elsa giggled. ‘I could never choose!’ she said. ‘I’ll marry you both, of course.’

That was good enough for me.

Max folded his arms and narrowed his eyes as he pretended to think. ‘Okay, that’s an excellent plan,’ he said, nodding his agreement.

‘Hey, kids.’ Papa folded up his paper and cupped his ear. ‘Can you hear that?’

We strained to listen. Other than the soft chatter of the other people in the carriage, I couldn’t hear anything. ‘What are we listening to?’ I asked.

Papa laughed. ‘Nothing! That’s just it. It’s the sound you hear when the carriage stops.’

He was right. The big wheel was still and now we were on top of the whole world. For a moment, I wondered if we might stay there for ever. I hoped so.

Then I remembered Mama’s Sachertorte waiting for us at home and decided that for ever might be a little too long.

Papa had stood up and was getting his camera out of his jacket pocket. He rarely went anywhere without a camera. Papa was Vienna’s finest family photographer. That’s what it said on his shop window anyway.

‘Come on, let’s take your picture while you’re on top of the world, eh?’ he said.

The three of us squashed together in front of the window.

Papa lowered his camera and frowned. ‘Not there,’ he said. ‘The sun is right behind you. You’ll be nothing but shadows. Come here.’ He waved a hand towards the door at the far end of the carriage. ‘Stand against this so the bright sky is in front of you.’

We shuffled to the end of the carriage and squeezed in towards each other.