In the frenetic, high-stakes world of Los Angeles first responders, police officers, paramedics, dispatchers, and firefighters race to answer emergencies that range from the catastrophic to the bizarre. Each call thrusts them into life-or-death chaos, and the series follows how they save strangers while wrestling with the fractures, losses, and longings in their own lives. Anchored by a veteran fire captain and a 911 operator haunted by her past, it swings from pulse-pounding disaster set pieces to intimate personal drama. Slick, sentimental, and unabashedly big, it celebrates the resilience of the people who run toward danger when everyone else runs away.