David was about our age. His hair was on the blond side; he had nice jeans on and a faded T-shirt in forest green. I could feel the day threatening to turn. He had more right to be there than we did, but he was uninvited. He came and the day I had planned so carefully was turning. Some people spoiled things. I cast another look at him, only to find him watching. He was humming as he came over and it took me a couple of seconds to pick up the melody.

“But if you’re the queen of the castle,” he said, “does that make us the dirty rascals?”

I had begun building a spliff. Now I let the lighter go out and blew out the tiny ember from what was a fast-diminishing eighth. The hash gave out a little plume of smoke. A few paces away, Em had her arm through Peter’s, as though holding him back.

“You tell me,” I said.

He sat down on the step, but not too close, and leaned back on his elbows, the toes of his shoes burrowing among the gravel. He was humming again and looking out over the lawns. Together, we followed the path of a white butterfly as it danced toward a sunken little pond, its surface covered in lily pads.

“These parents of your friend not about then?”

“In Boston for the summer,” he said. His voice was neutral, not posh, but not local either.

“And you’re what? Keeping an eye on it for them?”

I handed him the joint and his eyes met mine for a second before I could look away.

“Something like that,” he said.

We ate the picnic I’d brought under the pear tree. There were mini pork pies and Scotch eggs, pasties, a Walkers multipack of crisps, and everyone’s favorite chocolate bar: a Crunchie for Em, a Boost for Marcus, Peter’s Wispa, and a Mars for me. Em snapped a bit of her Crunchie off and gave it to David and then we all followed suit, so that there were four little pieces of chocolate lined up before him on the blanket like offerings.

“What should I have brought you?” I asked. We waited expectantly while he thought about it. Would it be something posh? Cadbury’s Bourneville, or—worse—a red Bounty? Perhaps he only ate Ferrero Rocher. In town, the nice cars had a tendency to slow down to let the kids in Marlborough College uniform cross the road while ignoring the rest of us. Then there were the plummy, carrying voices in Waitrose, the shops that sold evening wear, skiing and sailing kit, or displayed magnums of champagne in the window with strawberries around Wimbledon.

“Imagine it’s the last day on earth, just before the apocalypse. It’s the last chocolate bar you’re ever going to eat,” Peter said. I flashed him a look.