My feet seem to know where they’re going as I walk beside Nathan: left at the traffic lights, right at the church, pause and cross the road. Nathan’s voice is low and comforting, but I can’t understand what he’s saying. I can’t understand what’s happening to me. Strawberries? I’ve always hated strawberries. The dream I had of the picnic flits across my mind. Am I going crazy? Callie’s heart aches inside my chest. Could it be irrevocably tied to Nathan’s? But that’s ridiculous, isn’t it? A heart is just an organ.

Somehow I know we’re here. There’s a sense of home. And everything feels so surreal it’s almost as if I’m drunk. We slow and pause together at the end of the driveway while Nathan holds up his raincoat in one hand and pats each pocket to locate his keys. These houses still have the new build look about them even though they have probably been here over twenty years. Red roof tiles, and not a chimney in sight.

Nathan pushes open the gate that creaks and unlocks the glossy black front door that has a silver knocker, and I follow him into the hallway that holds the lingering smell of washing powder. There’s a giant print of the Eiffel Tower at night in a glossy black frame.

‘Make yourself at home.’ Nathan strides down the hall. It only takes him four steps to reach the kitchen. ‘Tea?’

‘Please.’ My fingers trail along the buttermilk walls as I follow him, and I rub the gloss white doorframe that leads to a cloakroom. I can’t stop touching things. Wanting to feel the solidity beneath my fingertips, if only to convince myself this is not a dream.

In the kitchen Nathan pulls mugs from the cupboard and fetches milk from the fridge.

‘Sugar?’

‘No thanks.’

Nathan digs a spoon into a caddy and heaps white granules into my drink, stirring as they sink, and I wonder if he’s heard me but before I can speak he glances at me and adds another half teaspoon.

‘I know you said no but it’s good for shock. Sugar. You still look really pale. Let’s get you sat down. Shall we sit in the garden?’ Nathan’s already hooking open the back door.

I’m desperate to see the rest of the house but he hands me a box of chocolate fingers. ‘Take these outside and get something in your stomach. I’ll sort out some proper food in a bit.’

The garden’s beautiful, its borders a riot of colour, and I remember Tom telling me how much Callie loved gardening. I lean against the fence, sipping my drink, while Nathan grapples with a large green umbrella, angling it so the table falls into shade.

‘Are you OK to grab the seat cushions from the shed?’ he asks.

The heat in the shed is stifling, but it still smells of damp and earth. Garden tools hang from the wall, mud stuck to the prongs of the fork. Stacked at the far end are bags of compost and lime, and there’s a shelf crammed with gardening books and packets of seeds. I spot the cushions half-hidden under a tarpaulin. I tug them and dislodge a flowerpot and as it tips over I see a glint of silver, and the biggest spider I’ve ever seen skitters across the floor. I shriek as I bolt outside.

‘You OK?’ Nathan takes the cushions from me.

‘Spider,’ I say, and I edge towards the corner of the garden as Nathan bangs the cushions together. Dust rises and falls.

‘You girls. Scared of everything.’ He smiles.

‘Not everything,’ I say. ‘Is your girlfriend scared of spiders?’

‘I don’t have one. Callie. My fiancée. She died a few months ago.’

‘I’m so sorry.’ And I am.

‘Thank you,’ he says. His face is closed as he drags the chairs over to the table, and I can see he doesn’t want to discuss Callie. Part of me is relieved. It’s difficult to know where to start and my head is still pounding with the effort of analysing everything that’s happening.

There’s a yapping from the garden next door, a small dog by the sound of it.

‘Bloody thing, I can’t stand it,’ Nathan says. ‘He belongs to the new neighbours. Callie would have a fit if she were still here. She hated Jack Russells with a passion. She was bitten by one as a child and terrified of them ever since. Funny, because she loved big dogs but she couldn’t go near a Jack Russell, even if it was on a lead.’

The garden tilts and sways – images pulse; Mrs Bainbridge, Casper – his needle-sharp teeth – Callie – the fear I felt at work. I stumble towards the back door.

‘Just nipping to the loo,’ I say. I need to collect my thoughts.

In the cloakroom, I perch on the lid of the toilet. Callie was terrified of Jack Russells. In the surgery, could I have felt her fear? It sounds crazy. I press my palm against my forehead. I’m hot. The sun is fierce outside and I reassure myself the heat is making me irrational or my medication is making me paranoid, but I know it’s more than that. I’m feeling what she felt but how can that be?

Nathan taps on the door jarring my already jagged nerves.

‘Are you OK, Jenna?’

‘Just a sec.’ I fumble for the lock – my hand won’t stop shaking – and I open the door not knowing quite what to say.

‘I’m sorry. It was stupid to take you outside in that heat when you’ve already fainted. You look so pale. You’re not going to keel over again, are you?’

‘No, I’m fine. Really. I just felt a little light-headed. I should probably go.’

‘Wait until you’ve eaten, at least, and you are feeling better. I’ll rustle up a bolognese. We can eat in the dining room. It’ll be nice to use it again.’

I hesitate. I do feel awful, and I did want to speak to Nathan.

‘Sorry. Am I being bossy? Callie said I could be sometimes. I mean well though. Honest. I’d be glad of the company,’ he says, and as he smiles I know I’ll stay.

‘OK. Thanks.’

* * *

‘How did you meet her? Callie?’ I’m sitting on a kitchen stool crunching on a piece of the pepper Nathan is chopping for the pasta sauce.

‘In a bar. I was on a night out with some lads from work. She was waiting to be served and laughing at something her friend had said. The sight of her took my breath away. She was the most beautiful woman I’d ever seen. Her friend went to the toilet and this sleaze-bag sidled up to her and started trying to chat her up. You could tell he was a chancer. Drunk so much he couldn’t stand straight.’ He frowns at the memory. ‘She turned away, and was obviously trying to brush him off, but he didn’t get the hint. I’ll never forget her face as I strode over, put my arm around her and kissed her cheek. “Sorry I’m late, darling,” I said, and he got the message and staggered back to his mates. She called me her knight in shining armour and that was it.’

‘Love at first sight?’ It had been a slow burn for Sam and me. We’d been friends for ages before we got together.

‘She was everything I wanted. Sweet, gorgeous and kind. Too kind.’ He slices the top from another red pepper.

‘Can you be too kind?’ I often think the world’s not kind enough.

‘Sometimes you have to learn to stand up for yourself, don’t you?’ His tone is soft but he is gripping the knife so hard his knuckles bleach white. He scrapes the vegetables from the chopping board into a saucepan, meat and garlic and herb tomato sauce already simmering, and my stomach growls.

‘Let’s go and sit in the lounge while that cooks through,’ Nathan says.

The lounge is immaculate. Furniture, shiny and white. A large cream deep-pile rug lies between the caramel leather sofa and the coffee table. At the far end of the room is another door which I assume leads to the dining room. Over the mantlepiece, in a silver frame, is a large photo of Callie. She’s standing on a rickety wooden bridge over a bubbling stream. She’s laughing. Her arm is outstretched, fingers splayed open, and a small stick tumbles from her hand.

My dream. It’s as though the bones in my legs have disappeared as I sink onto the sofa.

‘It was her birthday,’ Nathan says from behind me but I can’t tear my eyes away from the image. ‘She loved playing Poohsticks. We didn’t have much money at the time for an elaborate day out. She said she was thrilled with a surprise picnic though.’

I know she was. I want to tell him about the dream, the feeling of being utterly loved and utterly happy, but how could he understand? It sounds impossible. It is impossible. I’m dreaming about things that have never happened to me. That have only happened to someone I’ve never met. I press my hand against my chest and feel the thump, thump, thump of Callie’s heart inside of me.

And that’s when I know with absolute certainty. A heart is not just an organ. The heart stores secrets and lies. Hopes and dreams. It’s more than a muscle. I know it is.

The heart remembers.