I was sitting on a bench in St. James Park when Leo started work on me again. This time he was a lot more insistent.

He began with my left hand. My arm was stretched out loosely along the bench top. As I watched the fingers lifted and started to tap out a regular rhythm against the wood. I had been quite relaxed, enjoying the sunshine and watching ducks in the lake and young couples on the bank as they went through their elaborate courting rituals. So it took me a few seconds to realize that the finger-tapping was not my idea. Leo. It had to be Leo.

Da-da-DA-da-da-da-DA-da-DA-DA-DA.

Da-da-DA-da-da-da-DA-da-DI-DI-DI.

Over and over. My head was aching again, like a resonance to the tapped signal. The rhythm was inside me, and a harmony built to go with it.

Tom, Tom, the piper’s son.

Da-da-DA-da-da-da-DA-da-DA-DA-DA.

Why in God’s name would Leo be hitting me with that, an old children’s song? He wouldn’t. I had to be imagining it, mistaking a random thought of my own for Leo.

I sat quite still for another two or three minutes, trying to push the rhythm out of my mind. When it wouldn’t go away I stood up and began to limp slowly west along Birdcage Walk and on past the palace. The stiffness in my right leg was less and less, but I didn’t hurry. I had been told not to overdo things, even though the bone graft looked perfect on the X-rays. If only I were doing as well mentally as I was physically…

Leo was becoming more persistent every day. Last week there had been uncontrolled movements in my hand, and a couple of days ago it was double vision. If I could find out what was disturbing him, maybe we could get back to normal. No one at the hospital could offer any sort of explanation — relax, wait and see, was all they would say.