Zara was still a bit shy, but I chatted away about how my sister was going to have a baby, and asked questions about when Coco was tiny, and she slowly opened up.

‘She was so annoying,’ she confided. ‘She still is, but when she was little she was actually mad. She just threw things on the floor. One time I spent ages doing a picture, and she just came along and ripped it up. I was so sad. Mum made her draw me a new one, but it was rubbish, so I ripped that up. I wanted to make her cry, but she laughed.’

‘I’m the little sister in my family, so I must have been annoying like that to Sasha.’

‘Sasha is a nice name. But Ariel’s better.’ She looked at me with big eyes. ‘Is it nice to have the name of a mermaid?’

‘Usually, yes. Sometimes it’s annoying.’

‘My mummy’s called Abby. What’s your mummy’s name?’ she said.

I hadn’t even thought this might come up, and it was a stab in the chest, just for a few seconds. I took a deep breath.

‘My mummy died,’ I told her. ‘Last year. Her name was Anna. She was really nice. It’s just me and Sasha in our family now because our dad doesn’t live with us.’

Zara’s eyes were wide. ‘Oh no,’ she said. ‘Oh, poor you, Ariel.’ She patted my arm tentatively several times.

I blinked hard. ‘Thank you. It’s OK, sweetie. She got ill and in the end she couldn’t get better. We miss her every day. It’s funny to think that Sasha’s baby will only know her from photos.’

Mum would have been furious at Sasha getting pregnant, but I knew she’d have quickly come round. By this point in the pregnancy she would have been wildly excited about becoming a grandmother. I couldn’t bear to imagine it because she would have been so wonderful. She’d have known how to do all the things that baffled us.

I decided, again, to ask Joe to go and look for her in his world. I kept nearly doing it and then being scared. I knew that if he couldn’t find her – if she hadn’t been in town on 11 March 1999 – I would be utterly crushed. It felt better to think that she might be there than to know that she wasn’t.

‘You’re the baby’s auntie,’ Zara said, and I nodded. Her brow was furrowed. ‘I have an uncle I don’t know. He died before I was born. He was my daddy’s brother. My uncle Joe. That was so sad for Daddy and for my granddad and grandma, wasn’t it?’

I made myself look surprised. My heart was pounding.

‘It really was,’ I said. ‘Your poor daddy. Did your mum know him too?’