The Legend: A Moonlight Masquerade is a brief backstory for The Legend of Zelda: Majora's Mask included in the Official Nintendo Player's Guide. It acts a continuation of the Hyrule Archives: Legends of Zelda from the OOT player's guide, but only covers the events of MM.
A Moonlight Masqerade
Months after parting ways with his fairy sidekick, Navi, in the The Legend of Zelda: Ocarina of Time, Link sets off to search for his missing companion. But what he finds instead are a pair of pixie pranksters.
The two fairies are the accomplices of the devilish Skull Kid, and the three of them ambush Link as he gallops his horse, Epona, out of Hyrule and into an uncharted region of the Lost Woods. When Link regains his consciousness, he awakens to find Epona and his magical ocarina missing. Always quick to react, Link follows their trail.
BUt the Skull Kid is waiting for him.
Possessed and overcome by the evil power of the mask he stole from Hyrule's Happy Mask salesman, the Skull Kid jinxes Link and imprisons the boy within the body of a wooden, plantlike creature called a Deku Scrub.
Forced to cope with his strange, new form, Link the Deku Scrub must also deal with his forged alliance with Tatl, the feisty fairy partner of the Skull Kid. The fairy, carelessly abandoned by the Skull Kid who never thinks about how his actions affect others, reluctantly guides her new partner through a portal to a parallel world--a world where everyone is a stranger, yet each looks like the twins of someone Link has met in his homeworld of Hyrule.
The parallel world link stumbles into is one built around a towering clock. Time is everything in busy Clock Town, and it matters even more in the bustling burg since the moon has begun to creep threateningly closer and closer to the town.
The shadow that the moon has blanketed the land with has cast a dark pall over its inhabitants. Everyone's personal life has taken a turn for the worse, and it's all because the mischief spread by the Skull Kid wearing Majora's Mask and the influence his cursed guise has on the moon, the heaven, space and time. In three days, coincising with the town's Carnival of Time, the moon will crash. Only Link with his reputation as the Hero of Time, can save the doomed land of Clock Town.
The first to greet Link when he arrives in Clock Town is the Happy Mask salesman whom the Skull Kid robbed of Majora's Mask. The mysterious businessman strikes up a deal with the boy trapped in the Deku Scrub body: If Link can find his ocarina and use its power of time travel, the salesman will return Link to his original form. The Deku Scrub body will then become a mask that Link can don whenever he wants to assume his sylvan alter ego.
Link must right all the wrongs that the Skull Kid has cuased, and to do it, he must find masks to assume the identities and powers of other characters. But three days of masquerading aren't enough to set things right. Using his ocarina, Link will have to relive the same three days again and again, changing the courses of people's crisscrossing lives until he can finally rid the land of evil and set the world back on the right track.
If he's lucky......Time will be on his side.