The Coronation Ruby

The Coronation Ruby is the name of the elegant necklace gifted to Queen Juliana by her husband, Prince Bernhard, on her accession to the throne of the Netherlands in 1944.

Seven years later, in 1951, a first-kiss summer romance suddenly becomes a desperate, decades-long search for the royal-heirloom when the headstrong young Princess Sophia loses the bauble she has "borrowed" to impress her commoner boyfriend, Franz.

Also gone is the princess's diary, with its dangerous details about her forbidden romance and about the priceless missing necklace.

What is the connection between the diary, the necklace and the little British sports car purchased but then so quickly sold by the Queen's husband, Prince Bernhard? What does the shadowy palace footman, Willem Klein, know about the two kids, the diary and necklace, and the prince's car?