"The Bloody Sun" is the first of the Darkover novels set in "The Second Age" of the Terran/Darkovan contact. The Terran Empire has rediscovered its lost colony and has set up a spaceport on Darkover. But contact between Terra and Darkover is still tenuous at best. The "Comyn" rulers of Darkover are keeping Darkover out of the Empire and are keeping the Terrans restricted to "Terran Zones". In the decades since making contact, nothing has changed. With individuals, there has been communication and interaction between natives of Darkover and Terrans, but this has always been on a person by person basis and not any sort of policy. Some on Darkover, however, are pressing their lords to allow more interaction from the Terrans and to join the Empire so Darkover can move out of the "Dark Ages".
Jeff Kerwin was raised on Darkover in the Spaceport Orphanage. All that he knew was that his father was Jeff Kerwin, Sr, a Terran citizen. Working in the Terran service he finally gets an opportunity to transfer to a world of his choosing and Jeff chooses Darkover. He had been dreaming of Darkover his entire like and he felt as if something was missing from his life. On Darkover, Jeff tries to learn of his heritage and finds that, officially, he has none. The Orphanage which he so deeply remembers has no record of him ever being there. His bright red hair marks him as a member of the Comyn (telepathic ruling class of Darkover), though he believes himself to be Terran, and this sets him apart from any Darkovan citizen he meets. Because of his actions outside of the Terran Zone, the Terran authorities intend on deporting Jeff offworld. Instead Jeff follows a voice inside his head and joins up with the Tower of Arilinn. A Tower is where the major telepathic work on Darkover is done. He finds a sense of home at Arilinn and also learns that he will play a major role in shaping the future of Darkover.
This is the first time that the reader has had the opportunity to see the inner workings of a Tower on Darkover. Finally we get to see what it is that the Tower Technicians do and what matrix work is. The inner workings of a Tower have been hinted and spoken of by characters, but never before has it been seen in action ("The Forbidden Tower" was outside of a Tower structure).
While Bradley deals with the same main theme that she does in every other Darkover novel (a Terran finds himself having to adapt to Darkovan culture and the conflicts of two different cultures meeting and trying to understand each other), she tells a rather good story in "The Bloody Sun" and shows aspects of Darkover which have been previously left hidden. Bradley uses her main theme to explore how the Terran Empire is starting to change the lives of the Darkovans and how it is going to change the culture of the planet, which affects the Comyn ruling class. Bradley uses her main theme to show the changes in the Tower culture and how the telepathy can survive on Darkover. There are betrayals, heartbreak, and the amazingly fast romance that somehow morphs into a long lasting love which will last for years.
"The Bloody Sun" is one of the better Darkover novels and one which is as good a starting place as any for the series. It is a standalone novel, but ties into the novels earlier in the chronology and is the starting point for the "Second Age" of the Darkover/Terran era.