And then she told me.

Ava wasn’t my sister after all.

Or at least, she wasn’t totally my sister. She was Mark’s daughter. And I was Sean’s.

It was a shock. Of course it was a shock. Quite apart from anything else… why hadn’t I known? What was the point of sensing things, if I didn’t get a heads-up on something as fundamental as this? And when Mark finally came on the scene… why hadn’t I realised?

But it all made sense…

It made sense in the awful, jarring way that things do when they suddenly become true, and you realise why you’ve been smelling a rat all along, and the rat was the truth and you don’t like it any better for having found it where you live.

Maybe it was just that I hadn’t wanted to know. Perhaps I had picked it up, after all. I had definitely picked up something… something that Mark carried around with him.

Guilt?

Mum was very careful to make it clear that it wasn’t Mark’s fault, that he hadn’t known, that he’d been married to someone else. But that didn’t exactly reflect very well on either of them, did it?

Maybe it was just the kind of thing that happened when you were grown up. Like car accidents, or the little purple veins that Mum had on her thighs. These were things that you wouldn’t choose to have. But sometimes, they were difficult to avoid.

After Mum had finished telling me I was quiet. I looked at the sea and the people in it and thought that maybe it didn’t matter where any of us came from, or who we were biologically related to. Which was an odd thing to think, as odd as being dropped into somebody else’s life. It made me feel artificially calm, as if I was at a distance from myself and from everybody else too.

And yet up until that moment I would have said that Mum and Ava were the most important people in the world, and that nothing could possibly matter more than family and who your family were.

Mum asked me if I had any questions. I said, ‘Does Dad know? My dad, I mean.’

‘He does,’ Mum said. ‘He always has.’

So he’d lied to me and Ava, too. But maybe he had felt he had to?

‘He thought he was lucky to have her,’ Mark said, and there was something in his voice I didn’t like at all.

‘We should go back to the hotel,’ Mum said. ‘I don’t want to leave Ava alone for too long.’

‘She hasn’t exactly shown much sign of wanting to be with us,’ Mark said.

‘It doesn’t matter what signs she shows,’ Mum said.

I’d never heard them bicker like that before. They were beginning to sound like real parents.

I said, ‘Is there time for me to have a paddle before we go back?’

‘I thought you didn’t want to go into the sea,’ Mark objected.