The weather is foul. It hasn’t dried up overnight and the clouds are still grey and swollen. As I walk to work freezing raindrops gust into my face. I wipe my eyes with my fingertips and they come away dark where I’ve smudged my mascara, and I can’t help thinking about Callie’s black eye. Was it really caused by walking into a cupboard at work? A thought occurs. I could find out by visiting the dental surgery she worked at and asking the staff. Water has pooled by the side of the road and a car speeds past, instantly saturating me. Irritated, I switch my thoughts to something happier. The beach dream I had last night with the two little girls. Despite the science Vanessa throws at me I still secretly believe it is Callie and Sophie, and thinking of Callie’s happier times lifts my bad mood.

Pushing open the door to the surgery I’m thrilled to see John in reception with Linda.

‘How’s retired life?’ I ask as I step forward to give him a hug, but the expression on his face stops me.

‘Jenna. Can we see you in the office, please?’

Dropping my bag, I follow John. Linda shuts the office door behind us before bustling around the desk to her chair and sinking into it with a sigh.

‘After you left yesterday we had a complaint from a Mr Freeman.’ John stands behind Linda resting his hand on her shoulder but she shrugs him off.

‘Who?’

‘He’s just moved to the area. He rang with an emergency. His cat had been run over. He was told there weren’t any appointments.’

‘Who did he speak to?’ We have a policy of including our names when we answer the phone.

‘He said he spoke to you, Jenna, and that he was very distressed he couldn’t be seen but you told him it wasn’t our problem and put the phone down.’

‘Me?’ I lean forwards in my chair. ‘He said he spoke to me? I’ve never heard of him.’

‘Are you sure?’ John says. ‘Linda tells me you’ve been very… distracted.’

‘Positive,’ I say. The medication might make me forgetful but it doesn’t make me rude. ‘You believe me, don’t you?’

There’s a beat before Linda says: ‘He may have misheard the name. Let’s not dwell on it then,’ but as I leave the office she can’t meet my eye. We all know that Jenna doesn’t sound remotely like Kelly or Rachel and it stings that they might not trust me. This job is the thread linking me to my old life and if it’s severed I really don’t know what I’d do.

‘Perhaps it was Kelly pretending to be me?’ I haven’t time to filter the words that spring from my lips.

‘And why would she do that?’ There is no trace of the usual warmth in John’s voice.

‘To get me into trouble? You said she wanted more hours?’

Linda looks at me with an expression on her face that looks like sorrow. ‘Kelly’s a lovely girl. Jenna, we’re worried about you. You’re so preoccupied. Even when you’re here it seems your mind is somewhere else.’

‘Sorry. I’ll be more careful. I promise.’

Linda and John exchange a look before John says: ‘Back to work then, but if there’s anything you need to talk about. Anything we can do to help you, you know where we are.’ And as I leave their office, pulling the door behind me, their voices are low and muted and I know they’re talking about me, and as I pass Kelly in the corridor I can’t help glaring at her.

* * *

The next time the phone rings I am extra polite as I answer.

‘Hello, Jenna,’ says a voice that is warm and familiar. ‘It’s Nathan. I wanted to check you were OK? After Monday? I’ve been kicking myself for not taking your mobile number and I’m hopeless on social media, but I remembered where you worked. Hope you don’t mind me calling?’

‘No. I’m fine. Embarrassed but fine.’

‘I was wondering.’ I hear the tremor in his voice. ‘I remember you saying you don’t work Fridays and I’m owed some hours. Would you like to meet for a walk along the canal?’

I hesitate, but only for a second.

‘Yes.’

* * *

The flame on the Yankee Candle glows orange and the flat is soon fragrant with cinnamon. Lifting the cushions off the sofa one by one, I thump them to plumpness, wanting everything to be perfect when Rachel arrives. She used to come around once a week while Sam was playing skittles but that petered out after I fell ill. I’ve missed it.

Often during our girls’ nights in we’d binge-watch trash TV. Picking apart Don’t Tell the Bride, screeching at the groom’s choices. Tonight, the TV will remain blank and silent. There’s such a lot to talk about, it’s not always easy to snatch time to chat at the surgery. I scroll through Spotify trying to find something we’ll both like, settling on Ellie Golding. ‘Anything Could Happen’ drifts out of the speakers and I sing along as I straighten the rug.

When the doorbell rings I rush to answer it, enveloping Rachel in a hug as though I hadn’t left her at work only hours before. Her hair is shower damp, the smell of the surgery replaced with the sweetness of pear shampoo.

‘Sorry.’ She thrusts a carrier bag towards me and bottles chink together. ‘It’s Aldi. I’m too skint for Tesco – how depressing is that?’ But she smiles as she steps through the door. Nothing brings her down for long.

‘You needn’t have brought anything.’ But I’m glad she has. I’d meant to call into Asda on the way home but I’d forgotten. ‘Go and make yourself comfortable in the lounge and I’ll bring some drinks in.’

I don’t realise Rachel has followed me into the kitchen until I hear her say: ‘What the fuck, Jenna?’

Her bag thuds to the floor as she stands in the middle of the kitchen, turning 360 degrees, her mouth hanging open in shock as she takes in the photos of Callie, the scribbles on my Post-it notes, the sheets of information about Cellular Memory.

‘I know it’s a mess.’ I empty the carrier bag of the bottles she’s brought, Rosé wine for her, sparkling elderflower for me, and I take two glasses out of the cupboard. ‘But there is a logic to it.’ Pulling open a bag of sea salt crisps I shake them into a bowl, and I can’t resist popping one into my mouth.

‘This…’ She stares at me as I lick salt from my fingertips. ‘This isn’t normal, Jen.’

‘Having someone else’s heart transplanted into your body isn’t normal, Rachel. You know I wanted to find out what happened to Callie. For Tom and Amanda?’

‘Yes. But…’ She gestures towards the pictures.

I’ve never known her lost for words before, and I feel annoyed that she’s being so judgemental. She stoops in front of the fridge, studying the swirling lines of my mind map. I wait for her to speak.

‘Christ,’ she says, finally, straightening up, and I grab my drink from the worktop and sticky cordial splashes over my fingers.

‘Come through,’ I say picking up the crisps and striding from the room.

In the lounge, Rachel sits heavily on the chair and gulps from her glass, draining it in seconds before glugging more wine.

‘Callie’s fiancé, Nathan, rang me today.’

I can’t wait to tell her I’m meeting him on Friday, but I wait for her flurry of questions.

Instead, she quietly says: ‘Jen, I think you need to talk to someone.’

‘I was hoping to talk to you, tonight.’ My enthusiasm for having her here begins to wane.

‘I mean someone who deals with… well, in mental health. Vanessa?’

‘I’m not mad.’ Hurt she thinks I might be. I haven’t even told her yet about the episodes I’m experiencing, and loneliness wraps itself around me like a cloak as I know I won’t be able to now.

‘I don’t think you are mad.’ She speaks slower than usual as though choosing each word carefully. ‘But you’ve been under a lot of pressure: the operation, Sam, returning to work.’

‘Work is stressful.’ I clutch at the opportunity to steer the conversation onto a subject that isn’t Callie, or my state of mind. ‘What do you think of Kelly?’

‘She’s lovely. Young, of course. But eager to pitch in with whatever needs doing.’

‘I think she might be trying to get me sacked.’

The disbelief on Rachel’s face says far more than her words ever could. The gulf between us widens. The sense of loss is jagged and raw.

‘Forget I said that.’ I quickly say. ‘Shall we watch some TV?’

Turning off the music I aim the remote control, channel-hopping until I find an old episode of Say Yes to the Dress. We watch in silence, crisps untouched, as the bride squeals in delight at a delicate heart-shaped pendant and bracelet set. Sam bought me a bracelet just like it one Valentine’s, and I carry it around in the zipped pocket of my handbag every day so it’s always close to me. Now I wear a medical ID bracelet, and I miserably fiddle with the clasp. When the programme ends barely an hour later Rachel stands to leave.

‘Are you working tomorrow?’

‘Just for the morning,’ I say.

‘And afterwards? Will you speak to Vanessa? For me?’

‘I’ll think about it,’ I say but I’ve got no intention of ringing Vanessa tomorrow afternoon. I’m going to call into Callie’s dental practice and meet her colleagues. I am determined to find out whether the bruise on Callie’s face was really caused by her walking into a cupboard at work, or if there is another explanation.