“Ooh,” she said, eyes opening a bit wider at the mention of his name, “I’d have left my husband for him. We’d have spent a sweaty weekend consummating our affair in his Late Pleistocene weekend retreat.”

This was news to me, and I wasn’t happy knowing that my son might once—in an alternative future—be sleeping with another man’s wife. There was the ethical question of second homes, too.

“I never knew he would’ve had a holiday home in the Late Pleistocene.”

“One interglacial back so with good weather, nothing too bitey and only twelve thousand years ago, so easy access for Friday afternoons—the time engines would have gotten really clogged as soon as work ended.”

“If you must have a second home, best have it someplace where it doesn’t inflate house prices,” I mused. “Have you met him in this timeline?”

“No. I only got my Letter of Destiny last week.”

“Are you okay about it?” I asked, as my son Friday had also been summarized recently and was being a bit more reticent as to how it turned out for him.

“I’m fine about it,” she said cheerily. “Before, I suspected I might not amount to anything, and now I know I won’t, so at least it takes away the wearisome burden of delusive hope.”

“Very . . . philosophical of you.”

She thought for a moment.

“Will you tell Friday that Shazza says, ‘It would have been seriously good’?”

My son and father would both have been in the ChronoGuard if the engines hadn’t been switched off, so the seemingly pointless discussions on the might-have-been were not exactly relevant but certainly of interest.

I told her I’d pass on her message, and she gave a half smile before returning to her nails and bag of M&M’s.

The door to Dr. Chumley’s office opened, and a short, heavyset man walked out. He had prominent brow ridges, dark eyes, and a broad nose. He wore a well-tailored suit woven from three different colors of baling twine, and his head was topped by a shock of unruly hair that had violently resisted all attempts to be combed. When he moved, he had the side-to-side gait of a sailor, and the smell of woodsmoke and hot mud moved with him. This was not at all unusual. He was a resequenced neanderthal named Stiggins and soon to be, I assumed, divisional head of SO-13, the department that policed all unextincted creatures. Not just the legal ones like mammoths, dodos, saber-toothed tigers and himself but also all the ones that were illegal— Diatrymas, to list an example never far from the news, and a host of chimeras—creatures that had sprung not from the random machinations of evolution but from garden-shed laboratories of meddling hobby geneticists who should have known better.

“Hello, Stig.”

He gave a snorty grunt of pleasure, and we hugged and smelled each other—once in the armpit, once in the hair, as was the neanderthal custom.

“ Co-op generic shampoo,” he said with a grimace, the ’thal version of a smile, “but stored in a Pantene container.”