Its in the library
Firs, feed the mouse the moldy cheese from the dungeon. Then feed the mouse to the owl.
go into the dungeon
First press the metal plate that says McM on it then stairs come go down.Then you'll find the moldy cheese!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
get the moldy cheese and get the mouse in the castle
In the undergroud part of the libary
If you mean Poptropica, you can get the rat when you go to the castle and go to the left door, give the Moldy Cheeseto the rat, and he will come to you.
you put it in the room with the mouse in the astro knights castle and the mouse will eat it
It doesn't really matter.
with the manure
In the fountain
Defeat Mordred and get the orb
its in mordred's hideout