My dad had returned from naval intelligence in the Pacific in '45 and was assigned a plain-clothes detail out of the Federal Building in San Francisco. He was cool, quiet, and quite good looking.

In the same building worked a slim, stylish civilian de-briefer who also had top secret clearance. She like the look of the guy in the fedora.

San Francisco in the 40's; fog, cable cars, spies. Almost too Dashiel Hammet to be endured. They married.