‘You too!’ says Josie.

But Alix doesn’t hear her.

1 a.m.

Alix’s head spins. Tequila slammers at midnight. Too much. Nathan is pouring himself a Scotch and the smell of it makes Alix’s head spin even faster. The house is quiet. Sometimes, when they have a high-energy babysitter, the children will still be up when they get home, restless and annoyingly awake. Sometimes the TV will be on full blast. But not tonight. The softly spoken, fifty-something babysitter left half an hour ago and the house is tidy, the dishwasher hums, the cat is pawing its way meaningfully across the long sofa towards Alix, already purring before Alix’s hand has even found her fur.

‘That woman,’ she calls out to Nathan, pulling one of the cat’s claws out of her trousers. ‘The one who kept staring. She came into the toilet. Turns out it’s her forty-fifth birthday today too. That’s why she was staring.’

‘Ha,’ says Nathan. ‘Birthday twin.’

‘And she was born at St Mary’s, too. Funny, you know I always thought I was meant to be one of two. I always wondered if my mum had left the other one at the hospital. Maybe it was her?’

Nathan sits heavily next to her and rolls his Scotch around a solitary ice cube, one of the huge cylindrical ones he makes from mineral water. ‘Her?’ he says, dismissively. ‘That is highly unlikely.’

‘Why not!’

‘Because you’re gorgeous and she’s …’

‘What?’ Alix feels righteousness build in her chest. She loves that Nathan thinks she’s pretty, but she also wishes that Nathan could see the beauty in less conventionally attractive women, too. It makes him sound shallow and misogynistic when he denigrates women’s appearances. And it makes her feel as if she doesn’t really like him. ‘I thought she was very pretty. You know, those eyes that are so brown they’re almost black. And all that wavy hair. Anyway, it’s weird, isn’t it? The idea of two people being born in the same place, at the same time.’

‘Not really. There were probably another ten babies born that day at St Mary’s. Maybe even more.’

‘But to meet one of them. On your birthday.’

The cat is curled neatly in her lap now. She runs her fingertips through the ruff of fur around her neck and closes her eyes. The room spins again. She opens her eyes, slides the cat off her lap and runs to the toilet off the hallway, where she is violently sick.

Sunday, 9 June

Josie awakens suddenly from a shallow puddle of a dream, a dream so close to the surface of her consciousness that she can almost control it. She is in the Lansdowne. Alix Summer is there and calling her to join her at her table. The table is dressed with extravagant bowls of fruit. Her friends leave. The pub is empty. Alix and Josie sit opposite each other, and Alix says, ‘I need you.’ And then Josie wakes up.

It’s the buses.

The buses always wake her up.

They live right next to a bus stop on a busy, dirty road on the cusp of Kilburn and Paddington. The large Victorian villas on this street were built, according to a local history website, in 1876 for wealthy merchants. The road once led to the spa at Kilburn Priory and would have rumbled with the wheels of carriages and clicked with the hooves of horses. Now every grand villa on the road is split into clunkily converted apartments and the stucco exterior walls are stained the colour of old newspaper by the endless traffic that passes so close. And the buses. There are three on this route and one passes or stops outside every few minutes. The hiss of the hydraulics as they pull up at the bus stop is so loud that it sometimes sends the dog cowering into the corners.

Josie looks at the time. It is 8.12 a.m. She pulls back the heavy denim curtains and peers into the street. She is a matter of feet from the faces of people sitting on the bus, all oblivious to the woman spying on them from her bedroom window. The dog joins her, and she cups his skull under her hand. ‘Morning, Fred.’

She has a mild hangover. Half a bottle of champagne last night and then they finished with a Sambuca. Much more than Josie is used to drinking. She goes to the living room, where Walter sits at the dining table in the window overlooking the street.

‘Morning,’ he says, throwing her a small smile before turning his gaze back to his computer screen.

‘Morning,’ she replies, heading to the kitchen area. ‘Did you feed the dog?’

‘Yes, indeed I did. And I also took him out.’

‘Thank you,’ she says warmly. Fred is her dog. Walter never wanted a dog, least of all a handbag dog like Fred, who is a Pomchi. She takes full responsibility for him and is grateful to Walter whenever he does anything to help her with him.

She makes herself a round of toast and a mug of tea and curls herself into the small sofa in the corner of the room. When she switches on her phone, she sees that she had been googling Alix Summer late last night. That explained why she’d been dreaming about her when she woke up.

Alix Summer, it appears, is a reasonably well-known podcaster and journalist. She has eight thousand followers on Instagram and the same on Twitter. Her bio says: ‘Mum, journo, feminist, professional busybody & nosey parker, failed yoga fanatic, Queen’s Park dweller/lover.’ Then there is a link to her podcast channel, which is called All Woman , where she interviews successful women about being successful women. Josie recognises some of the names: an actress, a newsreader, a sportswoman.

She starts listening to one: a woman called Mari le Jeune who runs a global beauty empire. Alix’s voice in the introduction is like velvet and Josie can see why she’s pursued this particular career path.

‘What’s that you’re listening to?’ she hears Walter ask.

‘Just a podcast thing. It’s that woman, Alix, who I met in the pub last night. My birthday twin. It’s what she does,’ she replies.