Lynda and Walt seem like a lovely elderly couple. Married just a few short years ago, the couple lives with Lynda's mother in a riverside cabin in the mountains. The couple often go on hikes, where they learn to fly fish by the aid of helpful strangers. On the outside, completely harmless and welcoming. Who knows what happens behind closed doors. Alex Watcherson, 23, traveling across the mountains with her best friend Thomas Abe. They are enjoying hiking, fishing, and climbing their way through the mountains. When they meet Lynda and Walt on a remote mountain trail, they don't know what's going to hit them.