sentences:  Almost everything about the planet defies scientific theory, including its size, lack of hydrogen, its temperature, and the presence of free oxygen in its atmosphere.A consortium of spacefaring races, including humans, recruits Mesklinites, the centipede-like natives of the high-gravity planet Mesklin, to explore Dhrawn.The recruits include Barlennan and Dondragmer, respectively the Captain and First Mate of the "Bree", a merchant vessel of Mesklin, which sailed to Mesklin's south pole to rescue a probe sent by humans.