This isn't necessarily a "secret" trail, as it was once a trail that was maintained by the Sierra Club (founded by John Muir) for Yosemite NPS. After a rock slide, it became too dangerous to get into the trail, but once you climb over the boulders, the trail is fairly evident (although it's more difficult now, because it's not cared for). If you do this hike, make sure you are wearing actual hiking shoes and don't hike alone.
WARNING: The National Park Services advises people to not climb this trail. So, seriously, don't. :)
BRIGHT MIND - SUPERPITCH ENTERTAINMENT
Robert Mark Weinstein - LIBRARY OF THE HUMAN SOUL