The protagonist is the sharp-witted Dr. Peter Blood, a fictional Irish physician who had had a wide-ranging career as a soldier and sailor (including a commission as a captain under the Dutch admiral De Ruyter) before settling down to practice medicine in the town of Bridgwater in Somerset. The story is told from the perspective of an omniscient narrator, who enables the reader to see the thoughts and views of many different characters. The narrator - perhaps meant to be Sabatini himself - claims to have acquired the story from the ship's logs of Blood's longtime companion Jeremy Pitt.