In 1976 a Dallas police officer named Robert Wood was shot dead during a traffic stop, and Randall Dale Adams was convicted of the killing and sentenced to death. Errol Morris rebuilds the case through interviews with Adams, the prosecutors, the actual triggerman David Harris, and witnesses whose stories keep shifting under questioning. Stylized reenactments replay the shooting from conflicting angles, a milkshake cup, a flashing dashboard light, and a getaway car repeated each time a new witness changes a detail, turning the crime scene into an exercise in how unreliable testimony gets manufactured into certainty. Philip Glass's score runs under the interviews, giving the film an unusually formal, almost procedural tension for a story about a wrongful conviction. Morris's own investigation ends up doing the police work the original case never did, and the film's release helped get Adams's conviction overturned. It remains one of the clearest cases of a documentary changing the outcome of the story it was telling.