The caretaker shrugs and Lizzie waits anxiously until the playground clears, cursing the mothers who stand around laughing and gossiping. Go home, she thinks. Go home and let me get to my son.

She sees them surreptitiously appraising her, just like the women at the shelter did. They eye her up and down, her shoes, hair, eyebrows, waistline, nails, handbag. A million pitfalls, tests with no answers you can learn beforehand. Lizzie knows she’s got it all wrong. She’s got naturally thick hair that doesn’t need dyeing, enviable eyebrows and a small waist. Greg had told her that when she asked why women hated her. ‘And that brain. So sharp it’s a weapon.’

Greg was equally smart. Could keep up with her fact for fact, would lie in bed with her on Sundays and test her on marine biology. She had to take off a piece of clothing for every fact she got wrong. It was the only time she deliberately flunked a test.

‘True or false. Jellyfish have been around longer than dinosaurs.’ His hand was warm on her stomach.

Lizzie had pretended to think. ‘False?’

‘Lose the shirt.’

Lizzie is used to mums carrying an extra half-stone of digestive biscuits and leftover fish-fingers looking at her like it’s her fault they can’t lose weight. She wants to tell them WeightWatchers doesn’t work. Portion control and calorie counting does, but she can’t, not till she’s asked why she’s so thin, and even then, women don’t like her answer: ‘I simply consume eighteen hundred calories each day.’

Some women radiate warmth. If they were planets, those women would be Venus. Lizzie would be Neptune now, the inhospitable ice giant. Once she was the moon. Full of mystery and intrigue.

Once she had students who loved her. She got top marks, was on track to be deputy head. She was never supposed to be here, this mismatched version of herself, all loopholes and loose seams.

Lizzie cannot remember exactly when the two roads diverged in the wood of her life. She cannot pin it down so easily. Not like Alice in her Wonderland, though they do have something in common. She can’t go back to yesterday either. She was a different person then.

Now only Lenny draws warmth from her. He found a secret garden inside her. A disused well she never knew about. His heart, a bucket on a string.

At last the playground is empty of scooters and buggies. Crisp packets and letters-home-to-parents are all that remain as they cartwheel across the hopscotched tarmac and pin themselves to the climbing frame.