Peter said, “The Roman British elite only managed to score a few victories against the Saxons. It was a desperate time. They must have looked for hope—and what is Arthur, not dead but sleeping, if not an embodiment of hope? It’s a lovely story. But it’s got nothing to do with the truth.”

Perhaps, I thought. But unlike Peter, I had seen the Crypt, and its ancient, meticulous records. Perhaps I would be able to believe in Arthur—and it would be delicious if I could believe my remote great-grandmother had once kissed him, and in her way bested him.

We swapped the limoncello again, and I changed the subject.

“So,” I said, “what became of that invisible spaceship that took a right in the center of the Earth?”

He glanced at me, a bit wearily. “You still don’t take it seriously. George, something happened. It came from the sun. It made straight for the Earth, and it changed course. If it had been visible it would have been the story of the century.”

“I don’t see why you’re so fascinated by dark matter in the first place.”

He slapped the brick wall behind him. “Because for every ton of good solid brick, there are ten of dark matter, out there, doing something. Most of the universe is invisible to us, and we don’t even know what it’s made of. There are mysteries out there we can’t even guess at . . .” He lifted his hand and flexed his fingers. “Baryonic matter, normal matter, is infested with life. Why not dark matter, too? Why shouldn’t there be intelligence? And if so, what is it doing in our sun?”

I shook my head. I was drunk, and starting to feel sour. “I don’t understand.”

“Well, neither do I. But I’m trying to join the dots.” He leaned forward and lowered his voice again. “I’ll tell you what I think. I think there’s a war going on out there. Some kind of struggle. It’s going on above our heads, and we can’t even see it.”

I grunted. “War in Heaven? The dark against the light? I’ll tell you what this sounds like to me. Peter, your background’s showing. You’ve just somehow sublimated your Catholic upbringing into this great space-opera story of war in the sky.”

His mouth opened and closed. “I have to admit I never thought of that. Well, you might be right. But my psychological state doesn’t change the reality of the data—or the consequences. Just suppose you are a field mouse stuck in a World War I trench. What do you do?”

“You keep your head down.”

“Right. Because one misdirected shell could wipe out your whole damn species. That’s why some of us,” he whispered, “believe that it would be a mistake to announce our presence to the stars.”