Sirius Black at Godrics Hollow

[corinthum]

No: HPFGUIDX 59673

Karen wondered:

> How could Sirius Black have 
> turned up 'just' after Voldemoarts attack if he, SB, wasn't the 
> POtters secret keeper.
> 
> It wouldn't make sense to have someone as the secret keeper, if
every 
> one of their other friends knew where to find them!  Would it??
...
> Did the POtter family move in to the house when PP was given the 
> details as secret keeper - or am I really missing something here?


This depends on how one believes the Fidelius Charm works.  We really
aren't given much information regarding this.  Flitwick explains that
it is a complicated charm by which a specific bit of information is
hidden within a person.  I've detailed my theory of the Fidelius Charm
before, but I'll restate it since I can't seem to find it in the
archives.

Basically, once the Fidelius Charm is performed, the secret
information is removed from thought circulation.  Those who previously
had access to it lose it, and those who logistically should be able to
deduce the information are prevented from doing so.  

The former instance seems rather simple; people simply forget
something.  In Lily's and James' case, people forget where they live
(I'm assuming that the house in Godric's Hollow had been their home
prior to the spell; my theory does not require it to be otherwise). 
Sirius, of course, knew about the spell and knows perfectly well why
he can't remember their location.  I imagine some of their other
friends may have become rather perplexed, as they hopped on their
broomsticks to pay a friendly visit and realized they hadn't a clue
where they should go.  In this respect, I think most people would
figure out eventually that the Fidelius Charm had been employed.

The latter type of information loss seems a bit more complicated. 
Someone mentions that Voldemort could be standing outside the Potters'
window and not realize that they were there.  I picture a sort of
instantaneous amnesia, where a person looks in the window, sees the
Potters, and yet is unable to reach the conclusion, "Oh, the Potters
are here in this house."  That conclusion, logical though it seems, is
inaccessible.

However, once the Secret Keeper divulges the information, the charm is
broken.  People who had prior knowledge of the info regain that
knowledge, and people with sufficient clues pointing to the
information are finally able to make the logical conclusion.

So, as I see it, Sirius had probably become accustomed to wondering
about his friend, but not remembering where James lived.  One day, he
muses to himself, "I wonder if James is still safe, and I wonder where
he is..." and he naturally thinks in reply "He's probably at his home
in Godric's Hollow."  Panic time.  Because he is suddenly able to
remember, he knows the charm has been broken, and immediately races to
Godic's Hollow to see if the Potters are in trouble.  

So, according to this theory, the house in Godric's Hollow could
easily be one the Potters have lived in for years, but it isn't until
the spell is broken that their friends (and enemies) remember its
location.

- Corinth