A black car is pulled from the Rideau Canal near Kingston, Ontario, containing the bodies of three girls -- sisters Zainab, Sahar, and Geeti Shafia -- along with their presumed aunt, Rona Amir Mohammad. Later in the day, after family members report the women missing, Kingston police become suspicious. The stories told by parents Tooba Mohammad Yahya and Mohammad Shafia, and their eldest son, Hamed, don't match up with the rapidly gathering evidence.

An extensive investigation unfolds, revealing a troubling story of physical and emotional abuse in the Shafia home -- including threats of murder. Police begin to suspect that this is a quadruple "honour killing," planned and carried out to wipe away the family's shame caused by the eldest girls.

Two years later, Mohammad Shafia, Tooba Mohammad Yahya, and Hamed Shafia are tried for the mass murders, while a shocked nation follows the case until its gripping conclusion.