Tom Corbett Space Cadet #11

Space Cadets led by Captain Strong travel to a swamp planet to investigate why supplies they ordered haven't arrived, discovering that a trader named Jervis, dressed in a solar guard uniform, has been inciting the swamp people to kill space cadets and stop trading. After making contact with the swamp people's leader Gurli-Va and learning of Jervis's treachery, the cadets work to gain the natives' trust and plan to catch and punish the deceptive trader, with Mossback Bill agreeing to return to expose Jervis's crimes to the authorities.