This special episode primarily concerns one case. A father and daughter involved in a motor-vehicle accident arrive at the emergency room. The father, Gemmill (JOHN THADDEUS), received a minor scalp laceration. But his 7-year-old daughter, Corinna (NICOLETTE LITTLE), has a ruptured spleen and may need surgery. Carter administers to the little girl and begins a blood transfusion. Gemmill tells Lucy to call the girl's mother in Cleveland.

During the transfusion, Corinna unexpectedly loses consciousness. The staff realizes that the blood was typed correctly but it wasn't cross-matched, and Corinna is having a hemolytic reaction--her immune system is destroying the red blood cells. When Lucy tries to talk to the father, he's gone!

After talking on the telephone to Corinna's mother in Cleveland, Ohio, Lucy discovers that the father's real name is Nelson. Currently, in a bitter divorce battle with his wife, Nelson gave a false name to avoid prosecution for kidnapping his daughter. Meanwhile, the laboratory results show that Corinna has a cross reaction to minor antigens. Her mother's blood type doesn't match, but her father's blood is a perfect match--a 1-in-50 million chance. Nelson must be located in order for Corinna to survive. Carter's shift is over, so Greene takes the case. But Carter can't stop thinking about Corinna and searches all over Chicago for Nelson.

Meanwhile, Lucy also tries to locate Nelson after her shift ends. Corinna's condition worsens, and Benton needs to operate or else she will die. Benton performs surgery without the blood. Lucy and Carter team up and search all over Chicago, encountering dangerous situations including Carter's possible exposure to TB (tuberculosis). They eventually locate Nelson directly across the street from the hospital at Doc Magoo's, the local diner. Corinna finally gets her life-saving transfusion. The total team effort of the emergency room staff of Chicago's County General Hospital might save Corinna's life.