22 thousand fans are in Vegas for a life-affirming celebration of country music. Headliner Jason Aldean launches into his first set. Then the gunfire starts. They are trapped in a killing field.

A deluge of 911 calls. Are there multiple shooters on the Las Vegas strip? So many wounded, so many killed. Las Vegas Metro PD has officers down. They need to find the shooter.

At overwhelmed local hospitals, doctors triage the wounded, concentrating resources on treating those most likely to survive. Meanwhile, the SWAT team does not expect what happens next.

Country music artist Dee Jay Silver reunites with his infant son who was in a hotel room with his babysitter on the same floor as the shooter. Today, five years later, the survivors are still rebuilding their lives and trying to find closure.