The Maier files series

The lovebirds, Dieter and Lena get into a dizzying adventure in which everything is about the secrets of Otto Maier, missing bullion and esoteric treasures. They need to find their way through a maze of codes and machinations where nothing is what it seems. By delving into their own family history they open up “a Pandora’s box” of secrets. Maier Files is a puzzle, a mysterious trip, straight down the dark road into the unknown, a landscape full of codes, symbols and a hidden history of the world. https://www.maier-files.com/