This time it’s him who’s drumming his fingers on the Tesla’s steering wheel. They are back in a car park, at Truro railway station. The evening flight from Newquay to London was full.

  ‘Honestly, I’m feeling so much better,’ Kate says, stroking Stretch on her lap.

  After the results from the headset came through on his phone, she talked Rob into returning to London and said that she would drive him to the station. He was reluctant, suggesting he took a taxi, but he eventually came around to the idea, particularly as it turns out that Dr Varma is down for the weekend and has agreed to visit her this afternoon.

  ‘Are you sure you’ll be alright on your own?’ he asks.

  Despite his genuine concern, Kate can already sense Rob’s restlessness, his desire to be back on the train to London. ‘I’ll be fine. Dr Varma can look after me.’

  ‘Just remember to keep the house locked,’ he says.

  She sighs, turning to gaze out the window. Sometimes she thinks he forgets they’re in Cornwall not London.

  ‘I was going to give Bex a call,’ she says. ‘See if she fancies coming down for a few days.’

  Bex is her best friend, a bridge between her previous life and this one.

  ‘Good idea. We like Bex.’ He pauses, looking at her. ‘It’s all coming back, isn’t it?’

  ‘What?’ she asks, searching his face.

  ‘That brilliant brain of yours.’

  ‘Not if my painting’s anything to go by.’

  ‘What are you saying? You really captured Stretch today.’ He opens the car door. ‘Coming in?’

  ‘Mind if I stay here?’ she says, turning away. Something’s not right. Again.

  ‘Sure.’ He grabs his bag from the back seat and leans over to kiss her goodbye. She closes her eyes.

  ‘I’ll call you,’ he says. ‘Hope it goes well with Dr Varma.’

  Kate fingers the beach glass around her neck as Rob walks across to the station building. Just before he enters, a woman she doesn’t recognise comes up to him and they hug, smiling, laughing. Long face, like a horse. Rob isn’t a natural social animal – his first instinct is always to swerve away – but Kate can see he’s making an effort, eyes blinking. Maybe this woman is another investor.

  She watches the two of them chat and thinks how little she really knows about Rob’s London existence. It doesn’t bother her. He’d probably say the same about her life down here. The weeks are long without him and she’s made some good friends in the village. Who does he see in London? Or in Brittany, where he’s been going a lot in recent weeks? She’s not a jealous person, but she knows Bex thinks it’s odd that she’s never been to Rob’s flat in Shoreditch or his offices in Old Street.

  ‘Rob needs to know how much we love him,’ she says to Stretch, determined to shake off the unnerving thoughts that are starting to inveigle themselves in her head.

  She grabs the dog under one arm, climbs out the car and strides over to where Rob is still chatting. He hasn’t seen her approach. And then he turns.

  ‘Kate! Everything OK?’ he asks.

  She stands there, frozen to the spot, to the right of him. It’s that same tingling sensation again, a lurching nausea, only stronger this time – the disconcerting feeling that the man in front of her is both Rob and not Rob. Familiar but unfamiliar. Recognisable but a stranger. Not so much déjà vu as jamais vu.

  She inhales deeply, tries to focus on the red bricks of the station wall, something solid, definite, steadying. Her vision starts to blur. Is she about to have another migraine? This feels different. Rob is definitely acting strangely, like someone she doesn’t know.

  He’ll take over my life, me, you, the house, all that I’ve achieved, everything that’s precious to me.

  Kate swallows. She should have had the conversation with Rob, got him to talk more about his fear of doppelgängers, open up about his vulnerabilities. She turns towards horse face, whose strong nose suddenly strikes her as beautiful. Is that why Rob is behaving like this?

  ‘I just…’ She hesitates, sneaks a look at the woman’s slender figure.

  ‘Give me a second,’ Rob says to the woman.

  ‘Sure.’ She glances nervously at Kate. ‘See you on the train.’

  ‘I just wanted to say goodbye properly,’ Kate manages to say. ‘We both do,’ she adds, nodding at Stretch in her arms.

  ‘You need to rest,’ Rob says, hugging Kate and Stretch. She mustn’t cry. ‘And talk to Dr Varma. I’ve got to go.’

  She watches him walk into the station, wondering what’s happening to her.

  6

  Kate

  ‘Bex, I wouldn’t be asking you to do this if it wasn’t important.’

  Kate’s still in the Tesla at the train station car park, on the phone to her best friend.

  ‘You think he’s having an affair or what?’ Bex asks.

  ‘Maybe,’ she says, turning to stroke Stretch, who is asleep on the passenger seat beside her.

  ‘So what exactly am I meant to be looking out for?’ Bex asks.

  Bex is a schoolteacher. Lancashire born and bred, she is also Kate’s best friend, which is kind of her, as she doesn’t suffer fools gladly. They used to live in the same Wiltshire village and watch Fleabag while eating butter pie at her place. And now Kate’s asking a massive favour.

  ‘I want you to see if Rob’s with anyone when he gets off the train… and tell me how he seems to you,’ she says, realising how absurd she must sound. ‘How he looks.’

  ‘What? Mark him out of ten? He’s well fit, Kate. We already know that. Tens all round, even from Craig.’

  Why’s Bex in such an annoying mood? Probably because Kate’s asking her to intercept Rob at Paddington, see if he’s different in any way.

  ‘I was behaving really strangely just now,’ Kate says. ‘When I waved him goodbye.’

  Bex laughs. ‘That’s not like you.’

  ‘Seriously, Bex. Rob bumped into this woman at the station and suddenly he seemed like a different person… I can’t explain what I felt. I just know it was one of the weirdest moments of my life.’ Up there with the time she saw Jake, her ex, with another woman.

  ‘You was acting strangely? Or he was?’

  Bex’s accent might have been softened by years of living down south, but she’s lost none of her northern bluntness.

  ‘If I told you what I was thinking, you’d laugh at me,’ Kate says.

  ‘Do I ever? Even that time you tried doing the paso doble in the pub, I never once giggled.’

  She’s lying. They’d both laughed like drains that night. Her relationship with Jake was on the rocks and she’d needed cheering up.

  ‘I thought Rob…’ Kate’s words tail off. She’s crying. Stretch raises his head.

  ‘You alright?’ Bex asks, more gently now. ‘Is it that woman at the station?’

  Kate bites her lip, wondering where to start, how to explain. ‘There’s something else,’ she says, wiping away a tear, trying to keep it together. ‘Rob and I, we had a talk last weekend, about our worst fears. I was worried I might not be able to paint again, after the accident. And Rob, he said he’s scared of meeting his double. You know, his doppelgänger.’

  ‘His evil twin?’ Bex says. Kate can hear the amusement in her voice.

  ‘It’s meant to be a bad omen,’ Kate continues. ‘He met his once, a long time ago, but he’s worried about seeing him again. That he’ll take over his life. When I saw Rob off just now, I thought it was his double. Seriously. I know it sounds crazy, but it was fucking terrifying, Bex.’

  ‘OK,’ Bex says quietly, clearly surprised by Kate’s sudden outburst. She doesn’t often swear. ‘Maybe seeing Rob with this woman triggered something,’ she says. ‘Hardly surprising, all things considered.’

  Bex has helped Kate through some tough times in recent years. She never thought much of Jake, or the leaky narrowboat he and Kate lived on together in Wiltshire, and she’s been a big supporter of Kate’s new life with Rob. Thinks it’s time Kate got a break. And a twenty-nine-year-old tech toyboy fits the bill perfectly. Go for the money, girl.

  ‘Why don’t you call Rob now, make yourself feel better,’ Bex suggests.

  ‘I don’t want to worry him about it,’ Kate says. ‘And, you know…’ She pauses. ‘It might not be him I’m talking to.’

  Oh God, she’s sounding like a mad person. She pictures Bex pulling a face.

  ‘I just want you to tell me what you think, when you see him,’ she adds. ‘Reassure me that Rob hasn’t been replaced by someone else. That I haven’t just spent the night with a complete stranger.’

  ‘What time does his train get into Paddington?’ Bex asks.

  Kate closes her eyes with relief.

  ‘Four hours from now.’

  She loves Bex for being prepared to do this for her. She knew she’d be heading up to town today. She always goes to London on a Saturday to do the galleries. They used to travel together. But it’s still a big ask.

  ‘I could take a later train up to Paddington,’ Bex says. ‘To coincide with his. But you need to stop all this doppelgänger talk. I’m doing this to put your mind at rest. And if Rob’s having an affair, I’ll rip his balls off. Obviously. For you.’

  Kate has to smile. Bex can be salty like that. ‘Thanks, Bex. Really. Just make sure it looks like a coincidence, though. You being there.’

  ‘I’ll see what I can do. As it’s you. And because I know you’ll pay me back big time. Maybe a trip on his fancy yacht or something.’

  ‘Thanks.’ Kate pauses. ‘Rob hasn’t got a yacht, you know that. But I’ll buy you fish and chips. I told him I was going to call you, see if you’d like to come down here for a few days.’

  ‘Is that what you’d like? For me to come down?’

  ‘He’ll pay for your ticket.’ Rob always offers.

  ‘I’ll buy my own, thanks.’ And Bex always refuses.

  ‘Seriously, it would be nice if you could come,’ Kate says.

  Bex is currently single, a rare state of affairs. She’s not a stunner, but she does a lot with what she’s got. Kate’s seen how men notice her, the way she moves. She’s also thirty-three, like Kate, with no sign of children. Something else they have in common.

  ‘Actually, I could do with getting out the village,’ Bex says. ‘Might find myself a tasty Poldark, you never know. I’ll see what the trains are doing.’

  ‘Call me as soon as you see him?’ Kate says, much happier now.

  ‘How will I know what I’m looking for,’ Bex says, ‘if he, well, seems the same?’

  ‘You’ll know. Trust me.’

  7

  Kate

  It feels good to be back in the village after dropping Rob off at Truro. She was held up for ages driving through the narrow Cornish lanes – Saturday is changeover day for many of the local holiday lets – and to cheer herself up she pulled in at her favourite bakery and bought a cinnamon bun, an object of swirling, sugar-dusted beauty. She licks the last of it from her lips as she turns into the drive. To her horror, Dr Varma is already there, waiting by the front door. She should have come straight home.

  ‘I’m so sorry, Ajay,’ Kate says, showing him through the front door. She’s called him Ajay since their first session, at his request. Rob still uses his formal title. ‘I didn’t realise the time.’

  ‘It’s quite alright.’ Ajay smiles at her as he walks through to the kitchen and sits down at the table. ‘I was early anyway.’

  Kate knows he’s lying. She never used to be late for anything, hated it when Jake was not on time.

  ‘Thanks so much for coming,’ she says. ‘Rob tells me you were down for the weekend.’

  Ajay smiles benignly. She’s talking too much, not used to seeing him in anything other than a suit. This afternoon he’s wearing chinos, a polo shirt and deck shoes. The only clue he’s here for work is his familiar black attaché case.

  ‘Can I get you anything?’ she asks, hovering by the sink. ‘Tea? Something stronger?’

  ‘All good.’

  She can tell Ajay wants to get down to business. She sits opposite him and tries to relax.

  ‘Rob says you’ve been feeling a bit unwell,’ he continues. ‘Maybe a migraine.’

  She shifts on her seat and thinks back through the strange episodes of the last week. Ajay will be sympathetic. Scientific.

  ‘It was nothing,’ she says. She feels bad for wasting Ajay’s time, but she’d rather just confide in Bex for the moment.

  Ajay senses her discomfort and gives her one of his chubby, reassuring smiles. She’s forgotten what a good bedside manner he has. He won’t rush her. He will bide his time until she’s ready to tell him.

  ‘He also said you’re making fantastic progress,’ he continues, beaming. ‘Thought you’d really turned a corner when he arrived last night.’

  ‘I’ve been feeling a lot better,’ she says, watching as Ajay removes a laptop from his attaché case and opens it on the table. He pulls out a headset similar to the one that Rob put on her earlier, also covered with electrodes.

  ‘He’s asked me to run some more recognition tests – try to establish whether the part of your brain that was damaged in the accident has fully recovered.’

  ‘Recognition tests? Sounds suspiciously like police work,’ Kate says. When she did her interview for the super-recogniser job with Wiltshire Police, she was shown inverted faces and altered images. There was also a ‘before they were famous’ test, in which she had to identify celebrities from poor-quality images taken when they were young.

  Ajay smiles. He knows Kate never wants to work for the force again, but he agrees with Rob that her powers of recognition, almost non-existent after the accident, remain the best indicator of her brain’s overall recovery. The surgeon who operated on her talked of damage to her right temporal lobe, including the fusiform gyrus, the part of the brain that processes faces. He warned that facial blindness was a possibility. Kate was more worried about her ability to paint, particularly portraits of people.

  ‘We’re going to use the EEG headset to monitor a brainwave called a P3,’ Ajay says, checking his laptop.

  ‘What’s a P3?’

  ‘Electrical activity that occurs in the brain a fraction of a second after you recognise a face. The response spike is markedly stronger in super recognisers.’

  ‘Should I be flattered?’ Kate asks.

  ‘What’s interesting is that the reaction is involuntary – you can’t stop a P3 brainwave,’ he says. ‘It’s why they use it for lie detection.’

  Ajay turns the laptop towards her and explains that she’s going to be shown two faces for five seconds each. She’ll then be shown hundreds of random facial images in quick succession, about ten per second, using a process called rapid serial visual presentation, or RSVP. Buried among them will be the two faces she was shown at the beginning. If her recognition skills are working, the deeper cognitive responses of her brain will trigger a P3 spike.

  ‘Are you ready?’ he asks.

  She nods, adjusting her sitting position as he switches his laptop to full screen. A moment later, she studies each face for five seconds. First Brucie and then Jeff. Silly, she knows, but they used to use nicknames in the force when they were mentally storing images of faces, based on instant associations. Big chin? Bruce Forsyth. Prominent ears? Jeff Goldblum. It helps to make their faces stick.

  Brucie and Jeff disappear and a series of images starts to flash in full screen before her eyes. She doesn’t have enough time to clock each one in detail, but she’s aware that they’re what they used to call ‘dirty’ shots, when the faces are partially obscured.

  After thirty seconds, she feels tired. Despite the speed of the images, her brain is desperately trying to analyse each one, process it, match it against memories. The curse of the super recogniser. It’s like playing pairs on speed. Or Pelmanism, as her granny used to call it. Kate always used to win against her as a child, but it was put down to her younger brain rather than any special gift. She only discovered her ability to recognise faces a few years ago, although she should have seen the signs earlier. Whenever she watched TV, she’d recognise walk-on extras in the background that she’d seen in other films. She just thought everyone did.

  She doesn’t know how long the test lasts – two minutes, maybe longer – but she’s relieved when it’s over.

  ‘That was hard,’ she says, blowing out her cheeks. It feels like she’s just sat an exam.

  ‘You have to relax,’ Ajay says, studying his phone. ‘Allow the images to wash over you, let your subconscious brain do the work.’

  ‘I don’t think I spotted anyone,’ she says.

  ‘You did.’ He turns his laptop for her to see. There’s a graph on the screen and a noticeable spike. ‘Image number 213.’

  Jeff. ‘What about the other person?’

  ‘The spike was less pronounced.’ He scrolls through the rest of the graph and shows her more of a gentle hill than a mountain peak. ‘But it’s still an impressive response.’

  She’s not convinced. Brucie got away.

  Ajay pauses, shaking his head. ‘It’s still remarkable. Your powers of recognition are undoubtedly back, which is encouraging, given the damage that your brain suffered.’

  She doesn’t need reminding. Six months ago, returning home after a particularly difficult day at work, she drove into a tree just outside the village. Not that she can remember any of it. They think she fell asleep at the wheel. She was lucky to survive, given her traumatic brain injuries. No airbags in a 1969 woodie. After an extensive investigation, the police concluded that it was a tragic accident.

  ‘Does that mean my ability to paint will return, too?’ She glances over at the canvas of Stretch on the easel.

  ‘It should do. In time. Rob’s so pleased,’ Ajay says, putting away the headset.

  A part of her was hoping she could blame her funny turns on a still damaged fusiform gyrus. But if her brain is healing, it might not be playing tricks on her. And Rob might have been replaced by his double.