On March 13, 1964, Kitty Genovese was attacked on a street in Kew Gardens, Queens and left to die. Soon after, The New York Times published an investigative report asserting that 38 eyewitnesses saw the attack and retreated to their apartments, and the case quickly became a symbol of urban apathy. "The Witness" follows the efforts of her brother, Bill, as he looks to uncover the truth buried beneath the story. In the process, he makes astonishing discoveries about the crime that transformed his life, condemned a city, and defined an era.