Two months later, Amy was at home in the living room with her mum and Jack, helping to decorate their Christmas tree. A song called “Driving Home for Christmas” by a frightening-looking old man called Chris Rea was playing on the radio as she wheeled herself round the tree, draping the branches with baubles and tinsel.

She could do this easily, even though she was back in her old wheelchair, as it had been fixed. The wheels no longer resembled that of a broken Lodlil trolley. The whole thing had been given an overhaul and now she could guide herself round even quite a small space, like that between their Christmas tree and the wall, easily.

Every year, Amy loved decorating the tree. Jack was bored of doing it – decorating a Christmas tree is one of those things teenagers used to love doing when they were younger, but which they like to make clear to parents that now they find very boring.

So he was huffing and puffing and looking at his phone, when there was suddenly the sound of something being delivered through their letter box.

“Can you go and see what that is, Jack?” said Suzi.

Jack huffed and puffed and looked at his phone – which meant he didn’t want to do that either – but he went out of the room anyway.

“Oh right,” he shouted from the hallway, in his bored voice. “It’s Dad’s regular Christmas card.”

“Oh!” said Amy. “Bring it in!”

“Oh,” said Jack in a sarcastic voice, “bring it in!” (I should make it clear that although Jack had learnt some life lessons on this journey, he hadn’t changed that much. Not everyone changes that much during a story.)

“Well … yeah, do,” said Suzi.

“It’ll just be the same thing as ever,” said Jack, coming into the living room. He opened the envelope. “Just ‘Happy Christmas, Jack and Amy!’ on a card with some fake snow and glitter on … Oh—”

“What?” said Suzi.

“Some tickets have fallen out of it …”

Amy wheeled herself over to them and picked them up. “They’re train tickets! To Scotland!”

“What does the card say, Jack?” asked Suzi.

“It says, ‘Dear Suzi, Jack and Amy …’”

“Can you read it in a normal voice, please? Not a stupid one.”

“Hmm … OK. ‘Dear Suzi, Jack and Amy, I was wondering if you might want to come to Scotland for Christmas? And spend it with me? You don’t have to, but if you do, some rail tickets are enclosed … Love, Dad.” He looked up and, for once, his eyes were like a child’s, full of wonder.

“Yes,” said Amy. “Let’s do it!”

“Amy,” said Suzi. “I’m not sure …”

“Mum! You can’t say no to me!”

“What? Why not?”

Amy laughed. “Because I’m disabled!” she said.