The narrative follows Kit Silburn, a resourceful young seafarer who begins among wharves and hemp bales and rises to serve as supercargo aboard merchant ships. Through voyages to Yucatan, the Gulf, London, Marseilles, New Zealand, and Caribbean ports, he encounters storms, shipwrecks, a cabin burglary, arrest and imprisonment in the Castle D'If, a mysterious stranger, and eventual family reunions. The episodic tale blends maritime adventure, travelogue detail, and coming-of-age developments as it traces professional challenges, perilous rescues, and the emergence of love and personal responsibility.