For Peter Blood, scholar and doctor, the quest for justice is not an idle or abstract discussion. He is confronted with injustice of the most terrible kind: slavery. The terrible irony is that he is sentenced for performing an act of compassion, healing the wounded after a battle. "My business, my lord, was with his wounds, not his politics," he tells the judges. But bloody Lord Jeffreys, the King's judicial representative, will have none of it. He sentences Peter Blood to work in the plantations of the New World. Utilizing his medical skills, Blood escapes the worst of the sentence, and eventually, he organizes an escape and takes to the open sea as a pirate.

America and England have long had a love-affair with the outlaw, the individual who defines himself beyond the institutions of society. In England, Robin Hood is a prime example, as are the highwayman legends of Tom Evans and Dick Turpin. In the United States our outlaws have taken a decidedly western turn: Jesse James, the Lone Ranger, and Zorro. More modern examples are Bonnie and Clyde and Jimmy Valentine. With Captain Blood and The Sea Hawk (1915), Sabatini added immeasurably to the history of the outlaw ideal in literature.

In retribution for his suffering, Captain Blood, as he comes to be called, becomes the scourge of the Caribbean. "For what he had suffered at the hands of Man he had chosen to make Spain the scapegoat," Sabatini says. Thus, he who began as a peaceful doctor becomes a feared outlaw. His experiences as a slave have left him a bitter man. "It came to Mr. Blood . . . that man — as he had long suspected — was the vilest work of God, and that only a fool would set himself up as a healer of a species that was best exterminated." Fool or not, however, he continues to exhibit compassion. "It is not human to be wise," said Blood. "It is much more human to err, though perhaps exceptional to err on the side of mercy. We'll be exceptional." One of the complex paradoxes of Sabatini's fiction is this desire at once to hold up a shining vision of the ideal man and at the same time to reflect the contempt in which he generally seemed to hold the human race. Captain Blood is at once sardonic and remorseless and chivalrous to the point of being fool-hardy.
The justice Blood exacts on the Spanish Main is tempered by the love he has for his former master's daughter, Arabella Bishop. "The love that is never to be realized will often remain a man's guiding ideal," Sabatini observes. While his love serves to bring out the best in him, it also causes Blood anguish, for while he would have her admiration he attains only her contempt. The journey she takes to finally recognize Blood's essential nobility is long and arduous, but ultimately successful.