It's a parent's worst fear. Your children, all three of them, vanish in the wilderness. In this episode, we talk with three sisters, Megan, Erin and Kelsi Andrews-Sharer, about what started as a five-day backpacking trip in the Gros Ventre Wilderness in the summer of 2015. This story has so many twists and turns, we split it into two parts. In Part One, we find out how even when you know where you are, you can become trapped by the unexpected.