Kit, now aged sixteen, is being trained as a venturer by Captain Stephen, and is in the employ of Lady Leticia and Lord Morgan. Setting out for Lisbon on his first real voyage, in Stephen's three-master, he and his crewmates first have to deal with and repel a Barbary Corsair. Later, in Asturias, they defeat an evil wizard who has kidnapped some of the younger members of the crew. And finally, they manage to end the criminal career of a failed venturer who has turned to piracy; as reward, Stephen and Kit are invited to join the powerful society of Merchant Venturers of Bristol.