How do you get the key to door in the hidden lake on club penguin?

you have to be a member to play puffle rescue with the black puffle, somewhere in that game, you find the key

Be a member If you are then do section 1

[Section 1]
Go to the mine ( where cart surfer is) click the desk And click the black puffle
Get the puffle Wait.. For the gaint Squid Shaddow Follow The squid And Don't forget To collet the bubbles Or you wont make it.. Then Go through the Mini-maze And go to the Door with steps. Congratulations You have found the : Hidden Lake Secret Key