She starts doing jigsaws with her mother. Trains, and cats in wicker baskets. She and Christmas hate them, but there is something to be said about starting from scratch. Sorting out the pieces, outside, inside, filling in the sky. It is the opposite of what she’s done to Greg, dismantling their lives, piece by piece. Did she know what she was doing? Could she have stopped?

No, Beth realizes, with the clarity of chemical balance, sleep and no fresh scars. She was a train on a track heading towards disaster, imprisoned in her mind, but she isn’t that person any more. It is over. She is living through the aftermath, grieving not just for her son and her husband, but also for herself.

‘I forgive me,’ she says one day to Christmas, as she rubs Bio Oil into the dog’s scars and combs her bristly hair. She is getting shinier, and slimmer from all the walking, and has adopted a heartbreaking lopsided gait that makes Beth want to pick her up and carry her, but she doesn’t.

‘I forgive you,’ she says, to the face in the mirror that stares back at her, unflinching. ‘Life is a series of experiments and reactions to learn from. This has been another one.’

One day Greg calls to tell her Lenny is playing in a football tournament, then adds, ‘He misses you,’ in the flat voice of a parent trying to be a mum and a dad and finding he can’t. The voice of a parent who wants to give their child the whole world but can only manage a sliver.

She stays hidden at the football match, Christmas bundled into her large bag, like a giant Brillo pad.

Greg spots her and nods, once. She does the same back, forces herself not to wave, prays for her legs not to buckle. They do anyway, when Lenny runs out onto the pitch and turns to look for her. He spots Greg first and throws up both arms – Look at me, here I am – then keeps looking, frantically, along the rows of legs, until his gaze lands on her Dr Martens. She sees his mouth make the shape of her name – Mum – and has to clutch the seat in front of her. She is still that. It can never be taken away from her. She is still a mother, to two sons.

When the match finishes, Lenny runs to her with arms wide and his dad’s grin on his face. ‘Mum, did you see my goal?’

‘I saw it all. You were amazing.’

He throws himself at her then, knocking her backwards, and she clutches him until she sees Greg on the periphery, watching, and forces herself to pull back, wipe her eyes. ‘You look great. Haven’t you grown?’

Lenny beams as Greg comes over. ‘Dad, Mum says I’m taller!’