On a distant world far, far away, a swirling, gelatinous life form facing extinction sends out spores across deep space in search of a new home.
Then ... The spores encounter planet Earth and hitch a ride to the surface via a rain storm in, of all places, San Francisco. The view looks east from Lafayette Park towards the west-facing block of Gough Street near Clay in Pacific Heights (map). In the distance several towering apartments atop Russian Hill look out on the city.
and Now, this is the same view today taken from a little lower down the slope (trees prevent an exact match). Beautifully maintained, the two Queen Anne Victorians on the right are survivors, having barely escaped being torched by the fire that followed the 1906 earthquake.
... in 1906 ... here they were back then, with the scorched aftermath of Nob Hill behind them (that's the burned-out Fairmont Hotel on the hilltop), and what's left of downtown at far right. In the foreground Clay Street tees into Gough on the right side. The home on the left has since been replaced.
Then ... As the opening titles roll the camera looks from Lafayette Park along Clay. The tall, narrow 1250 Jones Street apartment building is seen where Clay crests the top of Nob Hill and the pointed peak of the TransAmerica Pyramid building is visible beyond another apartment highrise.
and Now, the same view is more or less unchanged 40 years on.
Across town the alien spores on rain-soaked trees and plants germinate and produce rapid cell growth before our widening eyes, culminating in a small pod with a pretty flower. Beware pretty things! The end of the world as we know it is nigh!