When Mack & Vonnie set out on their 10th backpacking trip, both have their own agendas aside from navigating the trails they know so well. For Vonnie, it's to say goodbye to Mack and a life together that has proven trying and is no longer worth the effort. For Mack, the trip is hopefully the last job he'll do for a few unsavory characters. The trip leads them somewhere darker, deeper and more dangerous than they've ever traveled before.