It is where the river is.
You need to make your way through the woods, build the boat, and enter the cave.
next to the cave
To get a Mission on Club Penguin go to the Ski Village and enter the Every Phoning Facility.
to find the cave on mission 8 you have to go to the place where a big log and a tree shows go to where a stick is and you are at the cave
go to HQ and there will be a book called secret mission go to that
find Herbert in the cave and stop him
First you have to be a member. Then you enter the secret cave and unlock it then its there
in the haunted house in the forest cave enter it
the dock i have completed the mission like ten times
They are in the cave. Click on one to make them into a circle of rocks.
Yes there is a secret mission on Club Penguin.