Two firefighters of Engine 17 of the Chicago Fire Department are brothers. Lt. Stephen "Bull" McCaffrey, the elder, is experienced, while Brian has labored under his brother's shadow his entire life. Brian returns to firefighting after a number of other career falters, though Stephen has doubts that Brian is fit to be a firefighter. In 1971, Brian witnessed the death of their firefighting father, Captain Dennis McCaffrey, while accompanying him on a call.