I hear Mack screaming my name. The terror in it seems to silence my fear enough that I reach out and grab for anything to stop my fall. Suddenly, I’m plummeting past a piece of the rock wall big enough for me to close my hand around. I grab it. I spend the next few seconds scrabbling with my other hand for another place to hold on to. But I find a handhold, and then I spend several more seconds moving first one foot, and then the other looking for a place to wedge my feet. When I feel secure—as secure as anyone can feel clinging onto a cliff wall over a thousand-foot drop—I rest my forehead against the wall, close my eyes and try to relearn how to breathe. “Aerin!” Mack calls from overhead. After taking another long breath, I lift my head to find him still leaning over. “I’m okay,” I

