The Sword of Rhiannon was originally published under the title “The Sea-Kings of Mars” in the June 1949 issue of Thrilling Wonder Stories. I’m not sure if the story was expanded for book publication. I can certainly understand the change of title. The Mars in this story is an ancient Mars that still contains plenty of water, not the dry and dusty global desert of Brackett’s other works.
The story opens with Matt Carse, who is sort of an Indiana Jones type archaeologist but with less ethics, being lured to a cavern on present day Mars. A two bit thief has found the millennia lost cavern in which the god Rhiannon was imprisoned. (This Rhiannon has no connection to the witch from Welsh mythology.) Rhiannon is something of a Prometheus figure, punished by the other gods because he gave advanced technology, specifically weapons, to some of the early Martian races. Continue reading