It took me a little while to figure this out. If you know Trollesund pretty well, you'll
notice that near the docks, there's a three arrowed sign pointing to the docks, the witch
consul, and the magisterium. Follow that arrow, and nose around for a huge brown door with
what look like bear claws on it. To the left of this, there's a little boy hanging around
the side who before this mission, said something along the lines of "I ain't tellin' you
my name". Talk to him again, and he'll offer to tell you a secret if you can beat him in a
race. Piece of cake: just change Pan into the fox and keep dashing til you reach the final
Northern Light-looking checkpoint. You'll then have to deceive him into telling you how to
sneak into the magisterium. Lyra ends up trading a secret for a secret: she tells him one
of the witch's bows by the consuls will make him fly LOL! After you're done talking to
him, head over to the left area and you'll see another gliding checkpoint. This one brings
you to the obstacle course you have to go through before you can enter the magisterium.
It's a pretty easy course, just keep using Pan's ermine insight to find what to do and
where to go next! And voilà, you're done!

One thing to remember in this game is talk to everyone. You will not be able to challenge
the boy to a foot race until you talk to everyone, go see Iorek, talk to people again, go
back and talk to Iorek (instead of it saying, "I don't think it's a good idea, Lyra until
he has his armor"). THEN you can challenge the kid to a foot race (the one outside the
Magisterium).

Change to the WILDCAT, and use dash the entire time. You'll have to race him back to the
dock area, near the trains and the bench.

Trick him, and he'll tell you where to go.

This will open up section 2 of Trollesund which is a series of Sloth swings, etc. across
beams and crates to get to the other dock.

Don't forget to use Ermine insight for tips on where you need to go. From there, it's
pretty self-explanatory.