In this tale, Earl Dumarest is on another starship, with another odd assortment of crew and passengers, when disaster strikes. The vessel is almost certainly doomed, but is saved at the last moment by a mysterious being, Tormyle, that turns out to be a living planet that is fascinated with humanity, death, fear, courage, and love.
It's a story that would have been right at home on "Star Trek" (as several of these have been), and I found this to be the strongest book in the series up to this point. The titular Mayenne is a sort of musical diva, who has an almost supernatural singing talent, and who immediately falls in love with Dumarest, as literally every other female character in these books has done.
Tormyle, the planetary intelligence, designs various trials and experiments to test Dumarest and the others, to evaluate strength, speed, intelligence, honor, and that old stand-by of forcing people to choose which of their companions will be killed and which will be spared.
I only have one more of these to do. You can find "Mayenne" at this LINK.
*That particular "honor" will go to "Jondelle," the tenth (and last) book on my contract.