(It is actually a LIBRARY SLIP.) Take the gold coin from the spaceship fountain (in the water), and tour the Mordred Museum. His library slip is in a stack of books and shows where the hidden "Secret of the Castle" is located.
Once you have the Slip, go to the castle library (first floor, to the right) and look in the Non-Fiction section, lower aisle, for the McM shelf.
it does not say library card you have to click McM because that what it says on the library card again not library card
On your library card{If you got it} it is at the top.It is underlined in red it's in non-fiction McM.Hope that helps!
You go to Mordred's Museum and click the books on the top floor. The manager won't let you have the books, but you get the card.
It's downstairs. Press one of the stacked books with a paper on it, and it should get you the library card.
The library SLIP is marked "Non-fiction McM", which is the lower aisle in the library. Press the spot on the shelf marked McM.
Mordred had often been going to the same location in the castle library (castle, first floor right).
The McM is on the bottom floor in the library. You can click on the mcm if you have the library card. The library card is in Mordred's house museum.
In the castle go to to the library (1st floor on right) find the little labels that say McM. Click it and stairs will appear.
There is a stack just the right of the museum guide. To pay your admission, get the gold coin from the fountain outside.
Click on his card in your items bag.
In Mordred's house
In the library on the bottom floor there is a green brick on the wall click on it .it will lead you to the dungen.