I'm not sure as I haven't read this novel specifically. But generally, it might be about a princess facing various challenges in the world, like political intrigue, battles for power, or maybe some magical threats.
The 'the princess against the world novel' might center around a princess who finds herself at odds with the world. It could be that the world around her is changing in ways she doesn't like, such as new ideologies emerging or new powers rising. She could be fighting to preserve the old ways of her kingdom or to protect her people from these new and perhaps dangerous elements. She may also face internal struggles within her own court or family as she tries to take a stand against the world.