‘Well . . .’ And then Paula felt slightly shamefaced for making her announcement in the first place, when there wasn’t even that much to tell. ‘Unfortunately we’ve sort of lost her again. She turned up at Mum and Dad’s party and then vanished, and we don’t know how to find her. To be honest, we don’t really know anything much about her at all.’

Lost her? Vanished? The drama! The intrigue! Paula found herself blinking at their delight and wonder, their eager stream of questions. It occurred to her that this was the first time anyone had actually expressed a positive opinion about Frankie’s existence, rather than it being this dirty little secret, a puncture wound to the Mortimer collective. She started explaining how badly her mum had taken the news, how the family had been rocked by the revelation, and how her dad had hit a brick wall in trying to track her down. Even nosy neighbour Lynne hadn’t been able to help.

‘Oh my God! This is so exciting. What a mystery! You’ve got to find her. There must be a way,’ Nicky and the others cried out, lunches forgotten.

‘Have you got a photo?’ asked Emma, who still had towel-marks on her forehead, like a pinprick rash, from where she’d been pressed down into her massage table.

‘Yeah, does she look like you?’ Amy asked, before rolling her eyes at her so-similar sisters and adding, ‘Because that is a curse and a blessing, believe me. Especially if everyone thinks you’re, like, the oldest one when you’re not.’

‘She does look like me,’ Paula replied, describing to them how she’d mistakenly thought Frankie was her, in the background of a photograph. ‘In fact,’ she added, reaching into the pocket of her robe and pulling out her phone, ‘I can show you.’ She pressed a few buttons. ‘Here,’ she said, passing it to Nicky.

‘Oh, wow!’ said Nicky, and then they were all crowding around to see, peering at the tiny lit screen and commenting, Gosh, yes, she did look like Paula. And yes, you could definitely tell they were sisters. What a surprise! What a bonus!

‘I know,’ Paula said, feeling rather overcome by their enthusiasm and excitement. ‘It’s so weird! After growing up with three brothers as well.’

‘Wait a minute,’ said Fliss, peering in for a closer look. Then she frowned. ‘I’ve seen her somewhere before,’ she said, forehead crinkling as she stared. She turned the phone slightly so that she could inspect the picture in a better light and nodded thoughtfully. ‘Yes. Definitely. Now let me think. Where have I seen her before?’

A gasp went up around the table. ‘Seriously?’ asked Paula, leaning forward.

‘Think, Fliss,’ Nicky urged. ‘Where have you seen her?’