She remembered Dylan telling her he had seen Mrs Elm near the care home. She thought about telling her this but decided against it. ‘Right.’

‘We only know what we perceive. Everything we experience is ultimately just our perception of it. “It’s not what you look at that matters, it’s what you see.”’

‘You know Thoreau?’

‘Of course. If you do.’

‘The thing is, I don’t know what I regret any more.’

‘Okay, well, let’s see. You say that I am just a perception. Then why did you perceive me? Why am I – Mrs Elm – the person you see?’

‘I don’t know. Because you were someone I trusted. You were kind to me.’

‘Kindness is a strong force.’

‘And rare.’

‘You might be looking in the wrong places.’

‘Maybe.’

The dark was punctured by the slow rising glow of the light bulbs all around the library.

‘So where else in your root life have you felt that? Kindness?’

Nora remembered the night Ash knocked on her door. Maybe lifting a dead cat off the road and carrying it in the rain around to her flat’s tiny back garden and then burying it on her behalf because she was sobbing drunkenly with grief wasn’t the most archetypally romantic thing in the world. But it certainly qualified as kind, to take forty minutes out of your run and help someone in need while only accepting a glass of water in return.

She hadn’t really been able to appreciate that kindness at the time. Her grief and despair had been too strong. But now she thought about it, it had really been quite remarkable.

‘I think I know,’ she said. ‘It was right there in front of me, the night before I tried to kill myself.’

‘Yesterday evening, you mean?’

‘I suppose. Yes. Ash. The surgeon. The one who found Volts. Who once asked me out for coffee. Years ago. When I was with Dan. I’d said no, well, because I was with Dan. But what if I hadn’t been? What if I had broken up with Dan and gone on that coffee date and had dared, on a Saturday, with all the shop watching, to say yes to a coffee? Because there must be a life in which I was single in that moment and where I said what I wanted to say. Where I said, ‘‘Yes, I would like to go for a coffee sometime, Ash, that would be lovely.’’ Where I picked Ash. I’d like to have a go at that life. Where would that have taken me?’

And in the dark she heard the familiar sound of the shelves beginning to move, slowly, with a creak, then faster, smoother, until Mrs Elm spotted the book, the life, in question.

‘Right there.’

A Pearl in the Shell

She opened her eyes from a shallow sleep and the first thing she noticed was that she was incredibly tired. She could see a picture on the wall, in the dark. She could just about make out that the picture was a mildly abstract interpretation of a tree. Not a tall and spindly tree. Something short and wide and flowery.

There was a man next to her, asleep. It was impossible to tell, as he was turned away from her, in the dark, and given that he was largely hidden under the duvet, whether this man was Ash.

Somehow this felt weirder than usual. Of course, to be in bed with a man who she hadn’t done anything more with than bury a cat and have a few interesting conversations from behind the counter of a music shop should have felt slightly strange in the normal run of things. But since entering the Midnight Library Nora had slowly got used to the peculiar.

And just because it was possible that the man was Ash, it was also possible that it wasn’t. There was no predicting every future outcome after a single decision. Going for a coffee with Ash might have led, for instance, to Nora falling in love with the person serving the coffee. That was simply the unpredictable nature of quantum physics.

She felt her ring finger.

Two rings.

The man turned over.

An arm landed across her in the dark and she gently raised it and placed it back on the duvet. Then she took herself out of bed. Her plan was to go downstairs and maybe lie on a sofa and, as usual, do some research about herself on her phone.

It was a curious fact that no matter how many lives she had experienced, and no matter how different those lives were, she almost always had her phone by the bed. And in this life, it was no different, so she grabbed it and sneaked out of the room quietly. Whoever the man was, he was a deep sleeper and didn’t stir.

She stared at him.

‘Nora?’ he mumbled, half-asleep.

It was him. She was almost sure of it. Ash.

‘I’m just going to the loo,’ she said.

He mumbled something close to an ‘okay’ and fell back asleep.

And she trod gently across the floorboards. But the moment she opened the door and stepped out of the room, she nearly jumped out of her skin.

For there, in front of her in the half-light of the landing, was another human. A small one. Child-size.

‘Mummy, I had a nightmare.’

By the soft light of the dimmed bulb in the hallway she could see the girl’s face, her fine hair wild from sleep, strands sticking to her clammy forehead.

Nora said nothing. This was her daughter.

How could she say anything?

The now familiar question raised itself: how could she just join in to a life that she was years late for? Nora closed her eyes. The other lives in which she’d had children had only lasted a couple of minutes or so. This one was already leading into unknown territory.