you go inside, get the moldy cheese and pull the lever down.
go to the secret door
On Astro Knights Island, there is a library slip in the Mordred Museum that shows he took the same item several times. (Get the gold coin from the fountain to enter the museum.) At the castle library "Mc-M" in the Non-fiction section has a shelf with scrolls on it. Push on the shelf to open the secret passage to the dungeon. (The library slip is for the book "Secrets of the Castle : The Shadowy World Beneath Your Feet".)
You will have to use the gold coin from the fountain to get the Library Slip from the Mordred Museum. Once you have it, you can click the McM shelf in the castle library and open the secret stairway to the dungeon.
On Astro Knights Island, there is a library slip in the Mordred Museum that shows he took the same item several times.Get the gold coin from the fountain to enter the museum. The library slip is in a stack of books to the right. In the castle library, the shelf Mc-M in the Non-fiction section has scrolls on it. Push on the shelf to open the secret passage to the dungeon.(The library slip is for the book "Secrets of the Castle : The Shadowy World Beneath Your Feet".)
Push on the shelf marked "Non-Fiction McM" on the lower aisle of the library. This is written on the library slip found at the Mordred Museum, which you need to open the passageway. Get the shiny gold coin from the fountain and pay your admission, and find the library slip in the stack of books.
Take the gold coin from the fountain and go to the Mordred Museum, where you will find the library slip. Go to the castle library (first floor right) and see the lower-aisle shelf marked McM. Press the scroll and the secret passage to the dungeon opens.
It is on the lower aisle (Non-fiction).You cannot enter it until you have the Library Slip from the Mordred Museum. Get the gold coin from the fountain, pay your admission, and find the slip in the book stacks. In the castle library, click the shelf marked Mc-M (alphabetical order of the books).
The Castle DungeonThere is an entrance to the dungeon from the castle library (and another one from Mordred's underground lab). If you get the gold coin from the fountain, you can recover the Library Slip from the Mordred museum. Then you can open the secret stairs into the dungeon.The Secret SocietyOnce you have the secret message from the Maid's room in the castle, you can get the new password from the girl in the Mill loft, and access the secret room under the village fountain.(see related questions)
In the castle library (first floor, right) there is a shelf marked McM on the lower aisle. Press it to open the secret stairway to the dungeon.
The dungeon entrance in the library does not use a key. Get the coin from the fountain, then the library slip from the Mordred Museum. Now you can open the secret passage in the castle library (Non-Fiction McM). However, once the dungeon is guarded, you will need the key to Mordred's laboratory to reach the cell again. (see related question)
There is no wishing well on Astro Knights island. There are :The spaceship fountain - there is a gold coin in the water, and if you take the secret message from the castle to the mill, the girl there will give you the password to open the secret passage under the fountain.The underground lab - Mordred's secret lab is hidden under the two bales of hay on the farm, and you will need the key from the secret room under the fountain.
There is no wishing well on Astro Knights island. There are :The spaceship fountain - there is a gold coin in the water, and if you take the secret message from the castle to the mill, the girl there will give you the password to open the secret passage under the fountain.The underground lab - Mordred's secret lab is hidden under the two bales of hay on the farm, and you will need the key from the secret room under the fountain.