The Shadow Prince is a book, officially published by Nintendo as the tenth installment in the Nintendo Adventure Books series of Choose Your Own Adventure publications. Link and Princess Zelda encounter a stranger in the woods, who saves Zelda's life and introduces himself as Prince Charles of Moria. He returns with them to Hyrule Castle and nearly everyone he meets is charmed by him. Link, however, is very suspicious of this character and his true motives.
The storyline is filled with puzzles which the reader is encouraged to solve in order to determine which course of action Link should take next. As is the case with many of these sorts of stories, several of the possible outcomes involve Link being killed in action.
Link and Zelda are exploring Midoro Swamp when they are suddenly attacked by a group of Moblins. Just when Link and Zelda seem defeated, a stranger appears, and the Moblins flee in terror. The stranger introduces himself as Prince Charles of Moria and claims to be traveling the world doing good deeds in order to become King of his homeland. After Zelda faints from an injury, the three return to the North Castle. Dowser the court hound growls at Prince Charles and tries to bite his neck. This is Link's first clue that this stranger might be more than he seems. The King of Hyrule meets Charles and takes note of a mysterious necklace he wears. Charles says he cannot take it off until he becomes King. Link is jealous of the stranger as he charms everyone in the castle and suggests having an archery match.
During the match, Link's arrow flies off course, and Impa informs Link there is powerful magic surrounding Charles, though she is unsure whether it is good or evil magic. The King then decides to show Charles the Triforce of Wisdom. After hearing about Ganon's attempts to steal the Triforce, Charles swears that he will protect it, and the King dubs him a Knight of the Triforce. The next day after Link visits either the Harbor Town of Mido, the Water Town of Saria, or follows Charles into the forest, the King calls a meeting.
After some strange events throughout Hyrule, the King decides to move the Triforce of Wisdom to the Fifth Castle of Ancient Hyrule. Charles is given task of moving the Triforce, which angers Link. Using an item Link obtained on his travels, Link reveals Charles' true identity as Ganon. Ganon takes the Triforce and flees the castle. Link follows and confronts him along with several Moblins in Midoro Swamp. Link destroys the necklace Charles was wearing and Charles' powers fade as he turns back into a weakened Ganon. The Moblins flee and Link returns to Hyrule Castle victorious.