"You may be right," he said. "But, first, I want to know something."
He had me relate to him everything that had transpired with the children after we left the house. He made me repeat several points and questioned me closely. He was interested particularly in what Summer had said, how she had said it and how she had acted. The whole thing was so clearly impressed on my mind, as it is today, that I'm sure I made few errors.
"Well," he said, when I had finished, "we'll never see either of them again, but I think I can say definitely they weren't killed in that explosion."
"I don't see how you can say that!" I exclaimed.
"You remember what I told you—that if Summer's existence had been reversed in time after she was born, she was existing somewhere else at the same time? Living normally as a younger child in one place, and as we knew her in reverse?"
I did remember it.
"Well, she was. But we thought she'd be a girl in both instances. When her time direction was reversed, so was her sex. Mark and Summer were the same person!"
I gasped. Wyn took a piece of hotel stationery from the rickety desk and scratched a zigzag on it with his pen. It was a figure like the one he had drawn in the library of our home, except that the top arm of this Z was very short.
He labelled the top arm of the Z "Mark," and the diagonal "Summer."
"My mistake was that I thought my energy explosion would be at B, throwing Summer back into a normal time direction. Instead, it was at A, reversing the time direction of Mark's existence: and the reversed Mark was Summer."