Sixth Cabin — Kathi Daley

Now you see her. Now you don't. When sixteen year old Emily Halliwell ran away from home she agreed to send her half-sister a photo every week to prove she was okay. And she did. For awhile. But then the photos stopped coming. Nicole Carrington, Emily's half-sister and the newest permanent resident of the Gull Island Writer's Retreat, decides to ask the Mystery Mastermind Group for help. The trail has gone cold but Nicole is desperate so the group decides to accept the challenge in spite of the staggering odds of finding Emily alive after all of this time.