The Map knows many things about the humans of Hogwarts Castle. It spreads out with a network of lines and loops of ink and creates a tapestry of truths. It paints facts and places and human lives, and the Map does not need to question—it knows.
When Moony, Wormtail, Padfoot and Prongs created it, in a corner of Gryffindor Tower with a shivering matchstick, a pile of parchment and glowing wands, the Map shook itself and rose to life.
(Or as close to life, at least, as the Map can be).
The Map has Rules:
Ink re-forms into Ink, reshaping itself into new shapes. Nothing is ever lost.
Sleep when Mischief is Managed; awake when a human Solemnly Swears. Deliver a series of pre-established remarks to select users.
Display the truth.
Dots will disappear now and again, and go Somewhere Else.
(Where Somewhere Else is, is of no concern to the Map.)
It knows the names of those who made it, but when they are gone, there is no one to know besides the dots that wander through countless paths and corridors. And in the silent grave where the Map has been left to sit, awaiting a new user, it watches them move back and forth, and it learns their names.
And in that silent corner, in whatever stilted, quiet, non-human way it can, the Map grows a mind of its own.
It collects names: Minerva McGonagall (sits by the window for twenty minutes before bed), Penelope Clearwater (rediscovers a secret passageway one night, followed by an eager Percy Weasley), Nicholas de Mimsy-Porpington (must be a ghost, given the way it ignores the Map's Walls), Nymphadora Tonks (finds increasingly more creative ways to escape the Castle), Bartemius Crouch (the second one, the Map knows, as another Bartemius Crouch has appeared once or twice, and made the first Bartemius Crouch stay locked in a bathroom stall for almost an entire night).
Fred Weasley and George Weasley.
Albus Dumbledore is the first name to do something truly strange.
It is not unusual for Albus Dumbledore to surprise—the Map has seen Albus Dumbledore do strange things before, change the very outline and Rules of the Castle, even—but this is different. There are many dots at the Astronomy Tower, yet Albus Dumbledore looks fainter, somehow, as if the ink cannot quite sink through the paper as it should.
And then Albus Dumbledore falls from the edge of the Astronomy Tower, and the Map does not understand, because the dot does not disappear with a flash in the way it normally does… it flickers and shivers and then vanishes, like the light on the matchstick did in Padfoot's hand decades ago.
The Map does not know how humans can flicker and vanish. Humans are not matchsticks. Something Else exists beyond the Castle, clearly, because humans come and go, but this is not a come-and-go…
This is just a go.
The Map watches the dots assemble on the grounds for days afterwards, but Albus Dumbledore is not among them.
The Map has always known that there are dots that are different. Dots that make other dots move away from them. Perhaps that is another one of the Rules—some dots repel others in the same way gravity forces pages to stay shut, in the same way the Map can be dropped to the floor—that same irresistibility.
Severus Snape is one of those dots, and crowds part in front of Severus Snape; they part and push and divide.
The Map learns many new things about dots in the time after Albus Dumbledore's dot disappears.
It has known that Severus Snape repels, knows that somewhere inside it are names and words to use against Severus Snape. But there are more things, things that break the Rules, things that the Map does not understand.
The Map learns that Bellatrix Lestrange does more than repel; Bellatrix Lestrange makes other dots splinter, and around Bellatrix Lestrange dots flicker and threaten to disappear.
And soon after come Alecto Carrow and Amycus Carrow, and they take over Rooms of their own, and pull in names, more names; keep them in their Rooms until those small dots all but fade away.
The Map watches the frequency of this phenomenon intensify, and then watches them, one by one, disappear into Somewhere Else, even when it is deep in strange places with Almost Prongs, who has no need for it but opens it sometimes… just to check, in justified paranoia.
And when Almost Prongs watches Ginevra Weasley's dot wandering alone in the corridors, the Map watches too, although it does not know why.
And then comes a time when Walls crumble, and the Map is left in chaos.
From the Grounds come masses of dots, and from within the Castle appear more, and suddenly there are dots everywhere, Walls destroyed and Staircases falling, and the Ink writhes before the Map in ways it never has before...
It is not for the Map to understand humans (after all, it is not alive, only in whatever way it is allowed to be), but there is something wrong, terribly wrong…
The Map sees Bellatrix Lestrange take names and make dots fade, sees Nymphadora Tonks—no, Nymphadora Lupin—flicker out, sees Colin Creevey, who used to wander the grounds for hours, flicker in a narrow corridor, sees dots repel, and splinter, and snuff out…
And the Map tries to gather them somehow, gather them within its parchment and keep them from falling away… Ink re-forms into Ink, it tells itself. Dots and names become Walls and Places, and nothing, nothing is ever lost—
It has known these names. It has read them, for a very long time. And even Bellatrix Lestrange was once a solitary dot, a Bellatrix Black clinging to an Andromeda Black, and that Bellatrix Black did not use make other dots flicker…
Humans are strange and confusing, and the Map does not know what it is supposed to do. Display the truth, say the Rules. But the truth is greater than only names. The Map wonders, how might it categorize dots that repel and dots that splinter and dots that cause others to flicker away… they are so different from Walls and Corridors, but they are even more different from other dots. Perhaps they should not be dots at all.
For the first time in its existence, the Map wishes it could display intent as well as location.
After it is all over, the Map thinks a lot, for a very long time.
(Or at least, as much as the Map can think. It is not really alive.)
In the end, the Map decides upon a Belief. It is the first Belief it has ever had.
It isn't a Rule, because it is not exactly based on what the Map can know. All the Map knows is that there are names and dots, and Walls and Corridors, and things happen and much of it is beyond the Map's reach. And all of it comes from Somewhere Else.
The Map stays with Almost Prongs for a long time, and is not used for most of that time, but it does not mind. It spends time developing its Belief, and watching the Walls and Corridors and Rooms return; everything is reshaped and rebuilt. The Castle regains its previous form.
The Map knows many names and remembers how they all flickered out, and it has wondered for a very long time where they have gone.
In the end, the Map thinks, maybe dots that flicker out also go Somewhere Else.
Not the same Somewhere other names go to, only to come back again later, but a different Somewhere.
It makes sense (or at least, as much sense as something can make to a Map).
So the Map decides on this Belief, and thinks that this is a Belief it likes. It has never Liked something before, but decides that this is a positive thing, like the Rules.
One thing, at least, has never changed about the Map: Ink re-forms into Ink. Nothing is ever lost.