Mary Rosenblum's Horizons is a near future SF novel with a somewhat old-fashioned shape and set of concerns. And I liked it for that -- it's very exciting, fast-moving, with some nice speculative elements. And with an engaging heroine. And really nasty bad guys. (Who espouse a philosophy I personally find repellent -- but which many might have at least some sympathy for.)
The heroine is Ahni Huang, daughter of the head of an influential Taiwanese commercial family. In the opening sequence she goes up to the North American Alliance's orbital platform, NYUp, to avenge her brother Xai's murder. But there she learns that Xai is actually alive, and acting against her family. She also discovers a secret on NYUp: a group of apparently illegally modified humans are living in microgravity, under the leadership of Dane Nilsson, the still "normal" chief "gardener" for the orbital.
After a confrontation with her father and mother, who are acting at mysterious cross-purposes, she returns to NYUp. The platform is under increasing tension. There is an independence movement, led by Dane, but it is spiralling out of control, moving too rapidly, apparently as a result of external agitators. Possibly these are controlled by Xai, who may be working with Li Zhen, son of the Chinese leader, and the man in charge of the Chinese orbital platform.
All this moves very rapidly to a confrontation -- the World Council military is pushed to act against the people of NYUp, particularly Dane. So Ahni must figure out who is really behind all these problems, and how or if she can get sufficient cooperation between Dane's allies on NYUp, between an asteroid-based pilot/smuggler, and between Li Zhen to prevent a true disaster from destroying everybody's hopes for the future.
I quite enjoyed the novel. At the same time it has some weaknesses. Notably the resolution of the plot is quite convenient -- it is exactly what we as readers want, but it comes too rapidly, too easily, but also after (I felt) a somewhat implausible raising of the stakes, increasing of the danger to the characters we care about. By which I mean that I think the end state could have been plausibly arrived at, but somewhat more slowly. But that would have been hard to make work novelistically. In the end Horizons is lots of fun, good solid SF -- not a lasting masterpiece but nice work.