Jack Howard, a typical American boy, is addicted to reading literature of the yellow-backed variety, despite the admonitions of his father. One day he dozes off to sleep, after devouring a thrilling story of the sea. The story of his dream is told in detail. While walking on the dock he is seized upon by some sailors and shanghaied in the most approved manner, being taken aboard a ship bound on a long cruise. He is secreted and overhears a plot of the sailors to mutiny, seize the ship and sail to a desert island in search of a treasure. One of the sailors produces a chart of the island and the tars leave the forecastle. Jack comes on, takes possession of the paper and is joined by the winsome daughter of the captain. It is a case of love at first sight. He shows her the chart and she takes him to her father, where he discloses the plot of the mutineers. The desperate men attack the captain and the loyal members of the crew and there is a fierce fight. Jack saves the captain's daughter, who escapes with him in the garb of a boy. They take possession of a small boat and put to sea, where they are captured by pirates. The sex of the girl is discovered, but Jack secures immunity for himself and fair companion by showing the pirates the chart of the treasure island. The pirates go to the island, taking Jack and the girl with them, unearth the treasure and are jubilant, but their joy is short-lived, as they are in turn set upon by another gang of pirates and the struggle is a bloody one. Jack and the girl are subsequently rescued from the pirates by the father of the girl and his gallant crew and taken aboard his ship together with the treasure, which is Jack's by right of having the chart. Jack asks the captain for the hand of the daughter and the mariner is only too pleased at the prospect of the union. They are wed and Jack awakens to find it all a dream and he is in despair. His reflections are rudely broken into by his father, who hauls him out of the garret and sets him at the irksome task of sawing wood.