The
Marauder's Map is a piece of parchment that maps the grounds of
Hogwarts School of Witchcraft and Wizardry in
J.K. Rowling's
Harry Potter series. The magic about the
Marauder's Map is that it shows the position, in real time, of whoever the person activating the map might need to see. The map also shows all the secret passages on
Hogwarts grounds. When it is not in use, the map looks like a plain square of blank parchment; to begin using it, one must hold one's wand to it and utter the words, "I solemnly swear that I am up to no good." To deactivate the map, the words are, "Mischief managed."
caution: small spoilers for book 3 in next paragraph
The map was created by
Moony,
Wormtail,
Padfoot, and
Prongs, otherwise known as
Professor Remus Lupin,
Peter Pettigrew,
Sirius Black, and
James Potter! When the four of them were at
Hogwarts, they made the map together, precisely for the kind of use that
Fred and
George Weasley put it to. And of course, what else would they use it for but making trouble? The four mapmakers were the same kind of troublemakers that
Fred and
George are, and at times, their map writes quirky little messages from them to whoever is using it, all in the hopes of promoting further mischief.
(for more on Moony, Wormtail, Padfoot, and Prongs, see Sirius Black)
The
Marauder's Map was first introduced in book 3,
Harry Potter and the Prisoner of Azkaban, when
Fred and
George Weasley gave it to
Harry after having used it themselves for a few years. The had found it when in
Filch's office awaiting punishment, and had taken it for their own use. Presumably,
Filch took it from a student years before, as a blank piece of parchment, and had kept it in his office, knowing that it was something tricky but not being able to do anything with it, as he is a
Squib.
When
Fred and
George passed it on to
Harry, he first used it to go to
Hogsmeade so he could join his friends.
Harry wasn't allowed to go since everyone was afraid
Sirius Black would come after him, but he snuck out through a secret passage using the map and his
invisibility cloak.
caution: spoilers for book 4 in next 2 paragraphs
Harry continued to use the map until about halfway into
book 4 when he lent it to who he thought was
Alastor "Mad-Eye" Moody.
Harry had taken the map with him to make sure that there was no one around while he was working on the clue to the second task in the
Triwizard Tournament, and on his way back to his room, he had noticed a dot that signified the presence of "
Barty Crouch" in
Professor Snape's office. He was singularly confused as to why the Minister of Magic should be here on
Hogwarts grounds when he was supposed to be very ill, but as it turns out, at the very end of the book, we find out that the map does not lie--
Barty Crouch Jr. had been there the whole time, using a potion to take the place of the real
Alastor Moody.
Unfortunately, very very unfortunately,
Harry did not know this at the time, and while he was busy being confused, he ran into
Snape,
Filch, and the impostor
Moody. As he was out after hours, he was under his invisibility cloak, but he still had some trouble getting himself away without being caught, especially when the map slipped out of his grasp and away from the protection of the cloak. It was the fake
Moody who helped him out (for his own reasons, revealed at the end of the book; see
Barty Crouch Jr.), as he alone could see
Harry, with the magic eye that he had taken from the real
Moody. After
Snape and
Filch had been got rid of,
Moody asked
Harry if he could borrow the map, and after that, it was in his possession until the final chapters of
book 4. Current possessor of the map is unknown.
please be patient as i attempt to add a node for Alastor "Mad-Eye" Moody and Barty Crouch Jr.