With the boys' new fort finally finished, everything that summer was going great. And then the killer showed up.
During the summer of 1987, from their tree house fort in the woods, neighborhood boys Tim, Scott, and Luke spot a man holding a gun to missing 16-year-old Molly Peterson's back. The problem is, nobody believes their story, not even the police. As search efforts to find Molly dwindle, the boys know that she, and the man with the gun, are nearby - and that they must now find and save Molly themselves. A growing sense of honor and urgency forces the boys to take action - to find Molly, to protect themselves, and to stand guard for the last long days of summer.