On Astro Knights island in the game Poptropica, Mordred's Lair is hidden in the castle. Inside the castle library (located on the right side of the first floor) collect the books "The Life of Mordred: A Cautionary Tale" and "The Mystical Weapon of Arturus" and click on the section of the library specified on your library card. A stairway will appear, leading you to Mordred's Lair.
just go to coordinates x=11 y=81
you run up to it and keep pushing. the wall will eventually crumble
after you have found the cosmic simbles you must then go to the staute and put in the simbles in order then find the key from the freckle face boy with the wierdos in purple robes will give you the key to his lair and it is under the hay!
get the missing page of mordreds jornal wich is under mordreds bed
mordreds lab is to the left of ye old windmill, between the two hay barrels
break it
56,52
in the upstairs of the museum.
In the museum.(the top floor)
You need to figure out the puzzle.
you go to mordreds secret lab
catch the mouse