When two friends return from a girls weekend vacation in Mexico, they find themselves stranded at the airport. Trying to get home safely, they board an airport shuttle for the short trip. But once their feet cross the threshold of the shuttle, a night that had started like any other turns terrifying, and the ride home becomes a descent into darkness.

On the night she broke up with her boyfriend, a Florida deputy sheriff, Michelle O'Connell was found dead from a gunshot in the mouth. Next to her was her boyfriend's semi-automatic service pistol. The sheriff's office called it suicide, but was it? FRONTLINE and The New York Times investigate this death of a young, single mother, and what can go wrong when the police are faced with domestic violence allegations within their own ranks.