I am a man of few secrets but the whole notion of secrets is pretty much one of the MacGuffins in my “Bloodhounds” series, the other as Neil and Amelia pointed is a lot of the plots also involve the distribution and smuggling of contraband materials.
You could say one you read the short descriptions of the stories they have a vaguely old school approach to storytelling, and you would be right. I crafted the set up with a vague Boy’s Own and Ripping Yarn tone with the intent of escapism. A lot of fiction and the moment has a series and sombre tone, even your superhero movies have a extentsialistic crisis element to them these days. So I deliberately set out for, mostly, clearcut good guys and bad guys. Thrown in colourful supporting characters and elements and hey presto, stories which (hopefully) are exciting, entertaining and fun.