Sun of Suns takes place in an immense habitable Dyson sphere (or something like a Dyson sphere) inclosing the star Virga. A freefall civilization — complete with barrel-like towns spun to produce gravity — has spread throughout the enclosed habitat. The book tells the story of Hayden Griffin, a young man seeking revenge against the nation of Slipstream for its war against his homeland (and the death of his mother) when he was a child. The environment is reminicent of Larry Niven’s Integral Trees novel, which took place in a similar microgravity environment (though in that case it was a stable gas torus around a star, rather than an enclosed sphere.
Sun of Suns’ civilization is more advanced than that of Niven’s, with small fusion suns tended by small nation-states and rocket-powered wood-and-steel ships capable of traveling the areas of “winter” between the suns. It’s a good read, full of shifting loyalties and strange-but-cool human habitats.