Thorby is a young, defiant slave boy recently arrived on the planet Jubbul, where he is purchased by an old beggar, Baslim the Cripple, for a trivial sum and taken to the beggar's surprisingly well-furnished underground home. Thereafter Baslim treats the boy as a son, teaching him not only the trade of begging, but also mathematics, history, and several languages, and sends Thorby on errands all over the city, carefully passing along information and keeping track of the comings and goings of starships, so that Thorby realizes that his foster-father is gathering intelligence, particularly on the slave trade. In addition, Baslim has Thorby memorize a contingency plan and a message to deliver to one of five starship captains in the event of Baslim's arrest or death. When Baslim is captured and beheaded by the local authorities, Thorby and local innkeeper 'Mother Shaum' convey the message to Captain Krausa of the starship Sisu. Because the 'Free Trader' society to whom Krausa belongs owe a debt to Baslim for his release of one of their crews from a slave-trader, the captain takes Thorby aboard the Sisu at great risk to himself and his clan.