The key to solving the toughest homicides lies somewhere in the final hours of a victim's life. In each one-hour episode, determined investigators must piece together events during this critical window to reconstruct the timeline, unlock the motive, and ultimately close in on the killer.

Delve into heart-wrenching crimes through the lens of real footage of victim’s last moments alive. Each hourlong episode tracks a different investigation in which law enforcement's efforts to solve a case hinge on dissecting the victim's final moments using their last interactions with family and friends, surveillance footage, text messages, and social media posts to build a timeline.