Herbert Bock (George C. Scott) is chief of medicine in a major teaching hospital. His wife has left him, he is impotent and his children have both disowned him. He is toying with the idea of suicide when patients begin dying, not from complications, but from the erroneous treatments the Hospital is giving them. People in the wrong beds are given wrong medicines, sent to operating theatres for incorrect surgery, and found in waiting rooms dead of natural causes. Barbara Drummond (Diana Rigg) has come to take her comatose father back to the Sioux reservation where he operates a clinic and they each reach out to each other for emotional support, as a shadowy figure stalks the patients and staff of the hospital.