Mr William Legrand, once a wealthy man, now lives a simple life on Sullivan's Island on the coast of South Carolina. His only companion is Jupiter, an old black servant. One day he finds a piece of paper near the wreck of a boat. By mere coincidence he discovers that it is not just a simple scrap of paper but a parchment which, if exposed to heat, shows an arrangement of figures and symbols. Legrand suspects it to be the record of the place where the legendary pirate Captain Kidd may have hidden his treasure. He is bent on solving the mystery of the message in cipher. In his eyes it is the promise of his return to his former wealth and position in society.
Careful examination of the document shows that its figures correspond to the letters of the alphabet:
Now, in English, the letter which most frequently occurs is e. Afterward, the succession runs thus: a o i d h n r s t u y c f g l m w b k p q x z. E (plays such an important part), that an individual sentence of any length is rarely seen, in which it (is not often used).
Finally Legrand is able to decipher the secret message and to solve the riddle it contains. Accompanied by Jupiter and his friend, the narrator of the story, he manages to locate the hiding place and unearth the wooden chest:
In an instant, a treasure of incalculable value lay gleaming before us. As the rays of the lanterns fell within the pit, there flashed upward a glow and a glare, from a confused heap of gold and jewels that absolutely dazzled our eyes.