Perched on the side of Munibung Hill, you will find this small cave. You will likely see it while walking up the fire trail towards the cache. Go for a little wander around and make your way down to the cave, which is where the cache is located.
You may need a natural TOTT (there is one stashed very closeby which worked perfectly for me) to retrieve and replace the cache from its little hidey ledge, and a torch would be helpful.
Good luck and have fun :)