He’d emailed her today, asking her to check the photos and rule out any that she didn’t want in the album. The edited video footage would be arriving separately, on a DVD and bespoke memory stick, he said, although his nephew had made a mini-highlights film, which he had attached, too. Paula had a few minutes to kill before she needed to start making dinner, so she’d sat down with the laptop, meaning to have a quick scroll through, out of interest – only to have one photograph stop her short. It was a perfectly nice picture of her cousin Lisa, beaming into the camera, and Paula herself was captured in the background with her dad. But then she looked again. Because she’d definitely been wearing a sleeveless pink dress for the party, and yet the woman behind Lisa was wearing a pale-blue shirt and jeans. So that was weird.

Frowning, Paula zoomed in for a closer look, realizing that it wasn’t her after all. This woman, although she had the same dark hair and beaky nose as Paula, was younger and didn’t have a fringe. And then she noticed the way the woman and her dad were looking so intently at one another, and it hit her like a shovel: oh my goodness. Was this her then: Frankie, the mystery half-sister? Surely it had to be!

‘Frankie,’ she breathed aloud, staring intently at the screen and drinking her in. So here she was: Paula’s little sister, right there at the party.

Obviously that was dinner forgotten about. Paula had gone clicking through all the other photos like a madwoman, searching desperately for another glimpse of her. Her efforts led her to one more image where you could just see the interloper entering the hall, her dark eyes wide and uncertain as she looked around; but that was it, the full extent of the evidence. ‘Oh. My. God,’ she murmured to herself, flicking from one picture to the other. Before and after, before and after. And indeed, you could see a certain strain on her parents’ faces in the later photographs, once Frankie had made her brief surprise appearance and had churned up an old secret. Captured by the lens, her mum’s mouth looked wobbly, her dad’s jaw taut, presumably as they tried to process what had just happened. Bloody hell. Blink and you’d miss it.

Paula had felt so unseated by her dad’s revelation; upset with him, with this Frankie person, with the whole world, frankly, for playing such a joke on her. And yet just look at this little sister of hers, sidling into the hall in that second picture, where she looked almost scared. That wasn’t the face of a family-wrecker, marching in, hell-bent on trouble, not at all. In fact she looked very much as if she was standing there, thinking: Oh shit.