A group of teenagers who spend a lot of time in the woods at a tree house they have built over the years have their lives changed dramatically when three of them witness the murder of a U.S. Senator. The only way they know he is a senator is the killer's addressing him by his title. The murder takes place just as night is falling and they can neither describe the killers nor their victim. They are reluctant to report the crime for fear the police will consider it a prank without supporting evidence. When the Senator's body is found at his house, the apparent victim of a botched robbery, the kids know they are into something more complicated than they bargained for. When they start to make inquiries on the internet, they suddenly find that they are being watched and wonder if whoever killed the Senator is sophisticated enough to track them through their computer usage. As they become further involved in the matter they contact the Senator's son and confide in him what they have seen and suspect. He arranges for private security for them and gives them access to his father's house in the Washington suburbs, where they find a cache of files the Senator has been compiling on a wealthy and influential contender for the presidential nomination. Eventually they go to the FBI and convince them that one of the most powerful men in the financial industry has been laundering money all his professional career for organized crime figures. After a failed attempt to kill them, they discover the secrets the files hold and help the FBI to find the evidence necessary to derail the plan that would have put the leadership of our nation in the hands of criminals.