I had spent a lot of time poring over the brochure Mark had given us, and the place didn’t disappoint. Inside the lobby there was vast reception desk, polished to a glasslike sheen, with clocks telling the time all around the world mounted on the wall behind it, and uniformed staff standing round just waiting to help us.

We went up to the room Mum and Mark were going to be sharing – Ava and I were next door – and it had a balcony with a sea view and the thickest carpet in the world and the biggest bed. Which was a strange and intimidating sight. It was just enormous, and so official, somehow. It announced that Mum and Mark were together the same way that thrones and crowns announce a king and queen.

I knew all about sex – they’d told us about it in school, but I’d already known, anyway – and I had assumed that Mum and Mark were doing it, and had decided that the best thing to do with this knowledge was to ignore it. Hard to ignore a bed that size, though. It wasn’t the kind of thing you could turn a blind eye to.

When I was a bit younger, I’d written several stories that sounded rather racy, because the heroines kept going down the corridors at night into the rooms of the men they liked and sleeping with them. That was before I knew the facts of life, and I thought sleeping with someone meant just that: dozing off in their arms, and waking up with them. I’d believed that was the closest thing men and women could do, the glue that kept marriages together, and an act so important that doing it on the sly was a scandal.

How silly and naïve I had been! And yet I hadn’t been entirely wrong. It did seem a big deal that Mum and Mark were going to be sharing a bed, when we’d never known them to before. Maybe it was going to be a test of whether they really liked each other. Or maybe it was a test for me and Ava, to see how we’d adjust.

The bellboy lifted Mum’s and Mark’s cases up onto the bed, and Mark tipped him with admirable smoothness, as if confident that he had exactly the right amount of money to give. The bellboy went out and Mum opened her case and Mark said, ‘I can unpack if you don’t feel up to it.’

‘No, no, I’m fine,’ she said, but she didn’t quite look it.

‘You should have a nap before dinner,’ Mark said. He turned to Ava. ‘How about we meet you on the balcony at six? We can have a drink and then go down for dinner. Look round the hotel if you want, but make sure you take Ellie. Stick together. We don’t want her getting lost.’

‘Of course I’ll look after her,’ Ava said. ‘You don’t need to tell me to. We’ll see you at six.’