This work touches on steampunk, and fantasy, and dystopian novels. But what it chiefly is is a philosophical thriller.
It opens with a debate between two characters who feature later, in an airship. But the chapter ends with a young man breaking a window, and the story takes off with that young man, a Catholic named MacIan, and the atheist whose window he broke, Turnbull, chasing around England trying to escape the police so they can fight a duel.
It features a car accident, a borrowed yacht, buying diplomacy in a shop, many long discussions, beer, swords, champagne, sunsets and sunrises, and much more.