There was Achilles, in the same kind of footsie babygro Donald had been wearing. Her little snuggly boy, who now looked hostile and rebellious if she suggested he change his shirt or put down his DS. He was sitting in Richard’s lap; Richard had just unwrapped an enormous, ridiculous puppet he’d brought back from a business trip somewhere. It was a huge gawky parrot with a purple and pink feathered crest and a manic grin. It had been hideous; Caroline had given it to Oxfam the second Christmas was over. In the picture, though, father and son were breathless with laughter and suddenly looked very like each other. It was a beautiful shot.

Caroline swore under her breath. Perdita had left, and the house – secondary glazed, of course, well set back from the road – suddenly seemed very quiet, only the ticking of the beautifully restored pale French grandfather clock in the hall disturbing the silence. Caroline didn’t want to look at photo albums any more. She wanted to gather her children close to her, feed them pie, apologise on some level for the family she had put in the photo albums, and the family they had turned out to be.

On impulse, she went to pick them up from school – normally they stayed late for homework hour so she could have some me-time. The other mothers at the gate smiled at her nervously, but didn’t engage her in conversation. Obviously they thought divorce was catching, like nits. Caroline ignored them. She also ignored the surprise – and, if she was being completely honest, worry – on the children’s faces as they emerged in their smart hats and blazers, marshalled by a teacher who looked suspicious that they were skipping homework club.

‘Is anything wrong?’ said Achilles.

‘Nothing at all, darling,’ lied Caroline. ‘I just wanted to see you, that’s all.’

‘Has something happened to Granny?’ asked Hermia.

‘No, but don’t worry, when it does, you’re getting a new pony. No, come on, let’s all go home together.’

‘I made a decoration!’ said Achilles, holding up a misshapen Santa with a huge head.

Normally Caroline would have smiled politely. Today she picked it up. ‘That’s fantastic!’ she said. ‘Shall we put it on the tree?’

The children looked nervous.

‘I thought we weren’t allowed to touch the tree,’ said Achilles.

‘I would never say that,’ said Caroline. ‘Did I? Did I say that?’

The children swapped glances.

‘OK, OK, never mind. Today it will be different. And I’ve made supper! Pie!’ She caught Achilles’ hand. Unusually, he let her hold it.

‘What kind of pie?’

‘Surprise pie.’

Their faces fell.

‘Now, tell me all about your day.’

And to her surprise, they did. Normally she got Perdita to pick them up for karate or swimming or Kumon maths or whatever it was they were supposed to have scheduled that evening. But just walking along with them, she was amazed when Hermia launched into a long and detailed description of how she and Meghan and Martha and Maud had been best friends, but now they couldn’t all be best friends and they had said to her that they would let her be best friends again when they’d got enough space and when she didn’t have a tummy any more, and Caroline listened carefully to the saga, which Hermia told in a completely flat tone of voice, as if of course it was the way of things that a group of small girls would turn on you sometimes and explain that you couldn’t be in their gang any more. She looked at Hermia’s wilfully black, tufty hair, inherited directly from Richard, and mentally contrasted it, as she so often did, with the smooth blonde locks of her friends’ daughters. Then she gave Hermia a big hug.

‘Are you looking forward to Christmas?’ she said.

Hermia shrugged. ‘Don’t know,’ she said. ‘I get scared at Grandma Hanford’s.’ Richard’s mother was a terrifying old horsey bag who lived out in the middle of nowhere in a spooky old house that she refused to heat.

‘Never mind,’ said Caroline. ‘We’ll have a proper celebration the next day.’

When they arrived home, Achilles unpacked his school bag. There were mountains of books and homework.

‘I know for a fact that Louis McGregor gets no homework till he’s nine,’ said Caroline. ‘Do you get this much every night?’

Achilles winced, and suddenly his face, which often seemed discontented and mulish to Caroline, looked simply exhausted. He was such a little boy. Such a small thing to be sitting in rows at old-fashioned desks, competing with other children who were also overscheduled and anxious and doing their best to please everyone. Caroline stroked his face. She wondered if it would really be the worst thing in the world if Richard stopped paying the school fees. Maybe if they went to Louis’ school, with their black history months and potato cut-outs and … No. That would be ridiculous.

A horrible smell was coming from the kitchen.

‘Shall we see if this pie is really terrible?’ she said. ‘And if it is, shall we call out for pizza?’

‘Can we eat it in front of the TV?’ said Achilles, pouncing on their mother’s moment of weakness. Between the Aubusson carpet and the pristine reclaimed oak floors, this was absolutely verboten; no food, shoes, wine or animals were allowed in Caroline’s front room. It was, she liked to tell the interviewer in the imaginary Homes and Gardens piece she occasionally did in her head, her oasis; a sanctuary from the hustle and bustle of London life. She would add that she often used the room to perform her meditations, even though she’d given up meditating when the divorce had started, because when she wasn’t busy doing something, she started thinking about how much she wanted to kill Richard.

Caroline rolled her eyes. ‘OK. Just this once.’

She scanned through the Sky TV guide.

‘It’s Christmas. They must be showing The Wizard of Oz.’

They were.

Issy’s favourite Christmas song was Sufjan Stevens singing ‘Only At Christmas Time’. It was so beautiful, and at the moment she seemed to be hearing it everywhere. It accompanied her as she did a huge food shop (Helena had come with her, then Chadani Imelda had kicked off like a maniac at the selection boxes, so Issy had sent them home), its refrain following her up and down the aisles: ‘Only to bring you peace/ Only at Christmas time/ Only the King of Kings … Only what once was mine’.