 Each subsequent book involves more ethical problems and philosophy, while at the same time the scale of action steadily increases.This is Lukianenko's only major work that is partially set in the same imaginary universe as the "Road to Wellesberg" series of short stories.In the novella "A princess is worth dying for", we follow Serge, a young retired sergeant of the Army of the country that now ceased to exist, who accidentally met and loved a Princess.