"The Angel of the Revolution" tells the tale of a group of self-styled 'terrorists' who conquer the world through airship warfare. Led by a crippled, brilliant Russian Jew and his daughter, the 'angel' Natasha, 'The Brotherhood of Freedom' establishes a 'pax aeronautica' over the earth after a young inventor masters the technology of flight in 1903. The hero falls in love with Natasha and joins in her war against established society in general and the Russian Czar in particular. "The Syren of the Skies" continues the tale of 'The Brotherhood of Freedom,' a worldwide brotherhood of anarchists fighting the world armed with fantastical airships. They must be quick in accomplishing their goals, as a dangerous comet is heading for the Earth.