The Solar Queen has obtained a trading contract on the planet Sargol and are building a relationship with the cat-like Salariki. The process goes slowly till the Salariki discover that the Solar Queen is carrying catnip and other plants from Terra that are unknown on Sargol. The traders exchange the plants they have for rare and valuable Koros stones and collect a native red-colored wood to exchange at home. A few days after leaving the planet, several members of the crew suffer from attacks and enter a semi-comatose state. Only 4 of the younger members of the crew are unaffected, including Dane Thorson. Upon exiting hyperspace on return to the vicinity of Terra, the crew discovers that they have been declared a plague ship!