In Tulsa, a vicious hammer attack leaves two young men clinging to life. Detectives race to catch the suspect before he strikes again. In Atlanta, detectives discover a selfless act performed by their victim led to his murder.

Police investigate the mysterious disappearance and possible murder of a 20-year-old single mother; detectives suspect the witnesses to a fatal shooting know more than they are saying; Dallas detectives embark on a manhunt across three states.