Sissy and her adopted brother, Sam, are embarking on a long-awaited camping trip in Michigan's U.P. They're both in college now and their parents are finally letting them plan a trip to the family's cabin on their own, but when Sissy's boyfriend bails on her for the umpteenth time and Sam's on-again off-again girlfriend gets sick and can't go, the two of them find themselves alone and get into far more trouble than two siblings ever should.