This is the third book in the Green Star series. The protagonist is Karn, a young hunter of the great trees but actually a man from Earth that has astrally projected himself- or something- to the world of the green sun. The details are not that important- what is important is that there is a princess to be saved! Karn and his fellow adventurers are on a mission to save the young princess of Phaolon from a rival city. In the process they just may prevent war from breaking out between the rival cities. Unfortunately, at the end of the previous book our hero looked on helplessly as the princess was rescued- and his friends made their escape- right in front of him, not realizing he was coming to their aid!
So here Karn and his companion, Klygon the assassin, find themselves in trouble in the city of Ardha. The mission they were on was to assassinate Niamh the Fair- she's the princess Karn is in love with- and while Karn wasn't really going to, he was using the opportunity to help her escape. Alas, he arrived too late, and now he must contend with Klygon, the homely little man who is his mentor in the assassins- and whose mission it is to kill Karn if the boy fails. Fun!
From there Karn travels all over the planet of the green sun on various adventures- a hallmark of these stories is the breakneck pace, the reversals of fortune, the struggling against overwhelming odds. Always while there is life there is hope, they say. I read this series as a kid and loved it, and to be clear these are pastiches- Lin Carter was known for his love of the genre, including the heavyweights like Edgar Rice Burroughs, and this is sort of a reimagining of Burroughs' stories about Carson of Venus. I actually prefer this series, though, to the Carson stories, and while Carter is regarded in some quarters as a bit of a hack writer, I like these.
The drawback here at times is the style of writing. Carter never says anything in a sentence if he can say it in a paragraph. Another flaw here is the casual racism. This is not unheard of in this genre, mainly because most of these stories are older and do not always age well, but it was wince inducing at times here. There is a black race of highly advanced savants, and the descriptions of them were just cringe inducing at times, even though they were referred to as being beautiful and whatnot. I think it's a product of its time- did they think no black people read sci-fi?- but that is clearly no excuse. And to be fair to Carter, he's writing a pastiche, and the sky- dwelling black race here brought to mind the black pirates of the Mars series- but it's still not acceptable.
As bad as that was, there are moments also.
"Down through the inconceivable panorama of of branches and layer upon layer of innumerable golden leaves filter the slanting emerald sunbeams of the Green Star. When these mighty beams of lucent jade strike the glittering golden foliage, their light is transmuted into a marvelous shade of green-and-gold whose radiant glory is indescribable and has to be seen to be comprehended."
"For a time we flew upward in a wide spiral, following the slanting glory of a green-gold sunbeam, until that uniquely Laonese sense of height informed us that we had reached the three- mile level."
There are interesting ideas explored here- the ethical implications of mind control and what makes humanity, well... human. There is a floating city of marvelous wonders and enough adventures to shake a stick at. And I just had fun with it.