The girl moved in at the weekend. Will didn't say anything to Camilla or me, but I walked into the annexe on Saturday morning still in my pyjamas to see if Will needed any help, as Nathan was delayed, and there she was, walking up the hallway with a bowlful of cereal in one hand and the newspaper in the other. She blushed when she saw me. I don't know why -- I was wearing my dressing gown, all perfectly decent. I remember thinking afterwards that there had been a time when it had been perfectly normal to find pretty young things creeping out of Will's bedroom in the morning.

"Just bringing Will his post," I said, waving it.

Steven

"He's not up yet. Do you want me to give him a shout?" Her hand went to her chest, shielding herself with the newspaper. She was wearing a Minnie Mouse T-shirt and the kind of embroidered trousers you used to see Chinese women wearing in Hong Kong.

"No, no. Not if he's sleeping. Let him rest."

When I told Camilla, I thought she'd be pleased. She had been so wretchedly cross about the girl moving in with her boyfriend, after all. But she just looked a bit surprised, and then adopted that tense expression which meant she was already imagining all sorts of possible and undesirable consequences. She didn't say as much, but I was pretty sure she was not keen on Louisa Clark. That said, I didn't know who it was Camilla approved of these days. Her default setting seemed to be stuck on Disapprove.

Will had apparently told her that she could use his computer, but she refused, in favour of using those at the library. I don't know if she was afraid of being seen to be taking advantage, or if it was because she didn't want him to see whatever it was that she was doing.

We never got to the bottom of what had prompted Louisa to stay -- Will just said "family issues" -- but she was a busy little thing. When she wasn't looking after Will, she was dashing around, cleaning and washing, whizzing backwards and forwards to the travel agent's and to the library. I would have known her anywhere in town because she was so conspicuous. She wore the brightest-coloured clothing of anyone I'd seen outside the tropics -- little jewel-hued dresses and strange-looking shoes.

I would have said to Camilla that she brightened the place up. But I couldn't make that sort of remark to Camilla any more.

Whichever it was, Will seemed a little happier when she was around. A couple of times I heard their conversations filtering through my open window, and I'm sure I heard Will laugh. I spoke to Bernard Clark, just to make sure he was quite happy with the arrangement, and he said it was a bit tricky as she had split up with her long-term boyfriend, and all sorts of things seemed to be up in the air at their home. He also mentioned that she had applied for some conversion course to continue her education. I decided not to tell Camilla about that one. I didn't want her to think what that might mean. Will said she was into fashion and that sort of thing. She was certainly easy on the eye, and had a lovely figure -- but, honestly, I wasn't sure who on earth would buy the kinds of things she wore.

On Monday evening, she asked if Camilla and I would come with Nathan into the annexe. She had laid out the table with brochures, printed timetables, insurance documents and other things that she'd printed off the internet. There were copies for each of us, in clear plastic folders. It was all terribly organized.

She wanted, she said, to present us with her plans for a holiday. (She had warned Camilla that she would make it sound like she was the one gleaning all the benefit, but I could still see Camilla's eyes grow a little steely as she detailed all the things she had booked for them.)

It was an extraordinary trip that seemed to involve all sorts of unusual activities, things I couldn't imagine Will doing even before his accident. But every time she mentioned something -- white-water rafting, or bungee jumping or what have you -- she would hold up a document in front of Will, showing other injured young men taking part, and say, "If I'm going to try all these things you keep saying I should, then you have to do them with me."

"If that's what you all want to do, then it's quite all right by me," Camilla said.

And my son smiled, as if she had said something particularly clever.

"Where did you find all this information?" he said, finally.

"So…" Louisa said, when all the questions had been asked. "We will be leaving in eight days' time. Are you happy, Mrs Traynor?" There was a faint air of defiance in the way she said it, as if she were daring Camilla to say no.

We all looked at him. There was a time, not that long ago, when any one of these activities would have been unthinkable. There was a time when Will would have taken pleasure in saying no just to upset his mother. He had always been like that, our son -- quite capable of doing the opposite of what was right, simply because he didn't want to be seen to be complying, in some way. I don't know where it came from, this urge to subvert. Perhaps it was what made him such a brilliant negotiator.

She raised her eyebrows at him. "Knowledge is power, Will," she said.

"Nathan? Are you still up for it?"

Will listened to her, and I could see him reading the documents she laid out in front of him.

"You bet."

"And… Will?"

I have to admit, I was secretly rather impressed by her. She was a resourceful little thing.

The girl seemed to physically deflate a little -- with relief -- as if she had half expected him to say no.

It's funny -- I admit, when she first wound her way into our lives I was a little suspicious of her. Will, despite all his bluster, had been vulnerable. I was a little afraid that he could be manipulated. He's a wealthy young man, despite it all, and that wretched Alicia running off with his friend had made him feel about as worthless as anyone in his position could feel.

He looked up at me, his eyes unreadable, and I felt my jaw tense. And then he looked at the girl, and smiled.

"Why not?" he said. "I'm quite looking forward to seeing Clark throw herself into some rapids."

But I saw the way Louisa looked at him then, a strange mixture of pride and gratitude on her face, and I was suddenly immensely glad that she was there. My son, although we never said as much, was in the most untenable of situations. Whatever it was she was doing, it seemed to be giving him just a small respite from that.

There was, for a few days, a faint but definitely celebratory air in the house. Camilla wore an air of quiet hopefulness, although she refused to admit to me that that was what it was. I knew her subtext: what did we really have to celebrate, when all was said and done? I heard her on the telephone to Georgina late at night, justifying what she had agreed to. Her mother's daughter, Georgina, she was already looking for any way in which Louisa might have used Will's situation to advantage herself.

"She offered to pay for herself, Georgina," Camilla said. And, "No, darling. I don't really think we have a choice. We have very little time and Will has agreed to it, so I'm just going to hope for the best. I think you really have to do the same now."

Louisa Clark had become, although neither of us said it, our only chance of keeping him alive.

"How wonderful," she replied.

I knew what it cost her to defend Louisa, to even be nice to her. But she tolerated that girl because she knew, as I did, that Louisa was our only chance of keeping our son even halfway happy.

Poor Della. I could see her fighting her instinctive urge to ask me about our future -- to consider how this unexpected development might affect it -- but I didn't suppose she ever would. Not until this was all resolved.

I went for a drink with Della last night. Camilla was visiting her sister, so we went for a walk down by the river on the way back.

"Will's going to take a holiday," I said.

We walked, watching the swans, smiling at the tourists splashing around in their boats in the early evening sun, and she chatted away about how this might all be actually rather wonderful for Will, and probably showed that he was really learning to adapt to his situation. It was a sweet thing for her to say as I knew that, in some respects, she might legitimately have hoped for an end to it all. It was Will's accident that had so curtailed our plans for a life together, after all. She must have secretly hoped that my responsibilities towards Will would one day end so that I could be free.

And I walked along beside her, feeling her hand resting in the crook of my arm, listening to her sing-song voice. I couldn't tell her the truth -- the truth that just a handful of us knew. That if the girl failed with her ranches and her bungee jumping and hot tubs and what have you, she would paradoxically be setting me free. Because the only way I would ever be able to leave my family was if Will decided, after all, that he was still determined to go to this infernal place in Switzerland.

I knew it, and Camilla knew it. Even if neither of us would admit it to ourselves. Only on my son's death would I be free to live the life of my choosing.

Dear Della. She could tell what I was thinking, even when I didn't know myself.

"It's good news, Steven. Really. You never know, this might be the start of a whole new independent life for Will."

I placed my hand over hers. A braver man might have told her what I really thought. A braver man would have let her go long ago -- her, and maybe even my wife too.

"Don't," she said, catching my expression.

And then Will got pneumonia.

"You're right," I said, forcing a smile. "Let's hope he comes back full of tales of bungee ropes or whatever horror it is the young people like to inflict upon each other."

Sustained by this unlikely picture, we walked, occasionally chuckling, all the way down to the boathouse.

She nudged me. "He might make you put one up in the castle."

"White-water rafting in the moat?" I said. "I shall file it away as a possible attraction for next summer's season."