Caelium - The Cerulean Airship, #3

In a race against time, Edmund Asher, Earl of Wyverstone and spymaster extraordinaire, has only one choice - to win. With one month left before the Engineers World Gathering and a powerful enemy on the loose, the odds are not favouring the Earl of Wyverstone. However, an unexpected request for help from the Engineering School in Paris could be the breakthrough he has hoped for - or The Cerulean Lady's misfortune.
The return of an old acquaintance bent on revenge doesn't help either, bringing England's spymaster on the verge of losing not only his position, but also the people he loves. Well-hidden secrets threaten to come to light, leaving Edmund with only one option - to catch his archenemy soon. Even if that means bending rules and joining Carmina Harcourt, the Classified Affairs' queen of disguise, in a deadly mission in France.
Alas, as he would soon discover, the man he chases is just a cog in a more complex - and darker - mechanism, spanning not only England, but the Continent as well. And he might be too late to stop it...