chunk: 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 all his life. Brian returns to firefighting after a number of other careers falter, 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.
  The longest serving of all the men at Engine 17, John "Axe" Adcox, served under the McCaffreys' father and was like an uncle to the boys when their father died. He attacks fires head on, but is concerned about Stephen's unorthodox methods and disregard for safety procedures. Helen McCaffrey is Stephen's estranged wife and the mother of their son, Sean. Helen has grown fearful of Stephen's dedication to firefighting and the risks he takes. While they were still in love, she separated from Stephen to protect herself and Sean.