It is the story of banished Asuras, and the uprising of the same for another fight against Devas.
I really loved the courage of the author to pick up a common belief of Hindu culture, and present it as an anti concept. He dares to turn the coin, and see the flip side of commonly known goodness of Devas, through Asura's eyes.
The book has amazingly unique contents. The parallel story of Bhadra, and origin of Sita are really pious. However, I had expected an equally powerful oratory to present them.