Among the natives of Block Island was a man named Lee. Born in the last century among fishermen and wreckers, he has naturally taken to the sea for a livelihood, and, never having known the influences of education and refinement, he is rude and imperious in manner. His ship lies in a Spanish port fitting for sea, but not with freight, for, tired of peaceful trading, Lee is equipping his vessel as a privateer. A Spanish lady who has just been bereaved of her husband comes to him to ask a passage to America, for she has no suspicion of his intent. Her jewels and well-filled purse arouse Lee's cupidity, and with pretended sympathy he accedes to her request, even going so far as to allow Senora's favorite horse to be brought aboard.

Hardly is the ship in deep water before the lady's servants are stabbed in their sleep and Lee smashes in the door of her cabin. Realizing his purpose, and preferring to sacrifice life to honor, she eludes him, climbs the rail, and leaps into the sea, while the ship ploughs on. As a poor revenge for being thus balked of his prey the pirate has the beautiful white horse flung overboard, the animal shrilling a neigh that seems to reach to the horizon, and is like nothing ever heard before. But these things he affects to forget in dice and drinking. In a dispute over a division of plunder Lee stabs one of his men and tosses him overboard. Soon the rovers come to Block Island, where, under cover of night, they carry ashore their stealings to hide them in pits and caves, reserving enough gold to buy a welcome from the wreckers, and here they live for a year, gaming and carousing. Their ship has been reported as a pirate and to baffle search it is set adrift.

One night a ruddy star is seen on the sea-verge and the ruffians leave their revelling to look at it, for it is growing into sight fast. It speeds toward them and they can now see that it is a ship—their shipwrapped in flames. It stops off shore, and out of the ocean at its prow emerges something white that they say at first is a wave-crest rolling upon the sands; but it does not dissolve as breakers do: it rushes on; it scales the bluff it is a milk-white horse, that gallops to the men, who inly wonder if this is an alcoholic vision, and glares at Lee. A spell seems to be laid on him, and, unable to resist it, the buccaneer mounts the animal. It rushes away, snorting and plunging, to the highest bluff, whence Lee beholds, in the light of the burning ship, the bodies of all who have been done to death by him, staring into his eyes through the reddening waves.

At dawn the horse sinks under him and he stands there alone. From that hour even his companions desert him. They fear to share his curse. He wanders about the island, a broken, miserable man, unwilling to live, afraid to die, refused shelter and friendship, and unable to reach the mainland, for no boat will give him passage. After a year of this existence the ship returns, the spectre horse rises from the deep and claims Lee again for a rider. He mounts; the animal speeds away to the cliff, but does not pause at the brink this time: with a sickening jump and fall he goes into the sea. Spurning the wave-tops in his flight he makes a circuit of the burning ship, and in the hellish light, that fills the air and penetrates to the ocean bottom, the pirate sees again his victims looking up with smiles and arms spread to embrace him.

There is a cry of terror as the steed stops short; then a gurgle, and horse and rider have disappeared. The fire ship vanishes and the night is dark.