NPR's Pentagon Correspondent, Tom Bowman, receives a shocking tip from a trusted source: A deadly explosion during the Iraq War was an accident—friendly fire, covered up by the Marine Corps—and the son of a powerful politician may have been involved. He partners with an old pal, Graham Smith, to investigate, and they discover the truth is even worse than the tipster realized. After dozens of interviews, the team patches together the story of the First Battle of Fallujah — the days and hours before the explosion — from the men who were there.