Athena, Bobby and the 118 "speed" to the rescue to save a family whose pick-up truck has been rigged with a pipe bomb which will detonate if the vehicle slows under 55 miles an hour. Meanwhile, Eddie has a rough transition into his new job, Buck makes an impulsive relationship decision and Hen is reluctant to accept her new partner in Chimney's absence.
Fast-paced exploration into the high-pressure experiences of police, paramedics and firefighters who are thrust into the most frightening, shocking and heart-stopping situations. These emergency responders must try to balance saving those who are at their most vulnerable with solving the problems in their own lives.