I turned along the promenade, where scattered cyclists were following a track marked out for them, swerving around pedestrians who apparently found the symbols on the concrete too arcane. At the distant limit of the dark sea the windmills resembled thorny sticks charred black. “Regale me with a little of it,” Bella said.

“I believe you’re some kind of parasite.”

“Do you believe everything you read?”

“If you’re telling me that book isn’t true, why were you so keen on reading it?” As headlights from a seafront car park caught her teeth bared in a smile, I said “And so anxious to hide it, which I’m sure you did?”

“You credit me with a good deal, Patrick.”

“I notice you aren’t denying it.” When her teeth continued glinting in the dark the headlights left behind, I said “If you aren’t a parasite, what do you want with my son?”

“For shame, Patrick. Just because you made an unsuccessful marriage needn’t mean that others can’t form meaningful relationships.”

With more anger than I cared to feel I demanded “So what does your relationship with Roy mean?”

“Mutual nourishment. Developing together.”

“Helping each other grow.” My cynicism might have been mistaken for bitterness. “I’ve heard you say that already,” I said, “and now I’ve heard it more than twice.”

“I doubt Roy or his mother would agree.”

“Of course they wouldn’t.” With an increasing sense of speaking in or to a dream if not a nightmare I said “They weren’t there the first time. Roy wasn’t even born.”

“What are you suggesting? Do put it into words.”

“It was you Thelma brought out of Third Mile Wood. It’s been you all the time.”

A dog approaching with its owner began to bark, though I couldn’t judge whether it was protesting at my fierceness. “You sound close to persuading yourself,” Bella said.

“And maybe other people,” I said, more a desperate hope.

“Do you sincerely believe that? Do you even really believe what you said about me?”

“I know you do, and that’s good enough.”

“You read minds, do you, Patrick? That’s a power I haven’t gained yet.”

“Which are you claiming you have?”

“You’ve had a hint of some. Perhaps you’ll invite more of a demonstration.”

This made me glance over my shoulder. Although I hadn’t thought we were far from the lights of the car park, the deserted stretch of unlit promenade seemed unnecessarily elongated. My companion’s outline appeared to squirm as if experimenting with its shape. Surely the illusion was produced by the dim relentless advance and retreat of the sea, and I said “You won’t deny where you got your phone or how.”

“I might or I might not, depending what you have in mind.”

“You took it from my aunt. You were with her on the roof.”