In 1819, France is surrounded by armies. With Russia in the north, the Karlsruhe Confederacy in the east, and a pirate kingdom in the south, Napoleon cannot break out, nor can the English Navy seem to break in. Europe teeters on the edge of a sword. Whichever side rules the air will win.

Celeste Blanchard, daughter of the Emperor’s disgraced Air Minister, is running out of time to develop an airship that can carry his armies to England and restore her mother to glory. But on a daring and desperate test flight, she is blown off course…and washes up, half drowned, on the shores of Cornwall, in the heart of enemy territory.

Loveday Penhale, cosseted daughter of gentry, has her own inventions to build, even as pressure mounts to behave like a proper young lady and seek a husband instead of a design for a high-pressure steam engine. But when Arthur Trevelyan, heir to the neighboring estate, Gwynn Place, asks for her help in rescuing an unconscious young woman on the beach, Loveday discovers an aeronaut and an inventor as skilled as she is. Between them, a friendship blossoms, and Loveday wonders if they might even pull off the impossible and invent an airship that will catch the eye of the Tinkering Prince Regent, who has offered a prize to anyone who can help England break the impasse.

Celeste’s loyalties are torn in two. If she is caught working secretly for France, she will lose her friend, the love of an honorable man—and her life. But if Napoleon learns she has betrayed him, she will be executed on sight.

Can friendship prevail in the face of war? Or is there a third solution—one where everything hinges on the bravery and daring of a Cornish debutante and the Emperor’s aeronaut?