Unnatural history

The Doctor regenerated in San Francisco at the turn of the millennium. When he returns there a few years later, it seems the catastrophic events that nearly sent the whole of Earth into cosmic oblivion have taken their toll. San Francisco was the anchor point, and a breach between dimensions has sprung up. All sorts of weird and wonderful creatures have turned up—griffins, unicorns—and things more sinister. The Doctor's companion Sam is exposed and becomes a changed person—literally. Her hair is dark, she has never met the Doctor in her life. With Fitz, he is able to convince her to help them put things right—to sacrifice herself so that the old Sam may return. For stalking the turbulent streets is the sinister Unnaturalist—a collector of genetic curios whose private collection will be much enriched by the Time Travelers.