Unnatural History

San Francisco's changed since the start of 2000. The laws of physics keep having acid flashbacks. There are sightings of creatures from outside our dimensions, stranded aliens and surrealist street performers. The city has become a mecca for impossible creatures, those who revel in them - and those who want to see them pinned down and put away. And beneath the waters of the Bay, something huge is waiting.

The Doctor and Sam find their pasts catching up with them - in Sam's case, a past she didn't know she had. Time is running out for the city, and the Doctor may have to sacrifice an old friend to sort everything out.

But who's trying to sort the Doctor out?

This is another in the series of original adventures for the Eighth Doctor.