Increasingly, patients of a large New York hospital find themselves on the table of pathologist Jack Stapleton and his colleague Laurie Montgomery. A young man who breaks his leg suddenly dies from cardiac arrest. Then a blooming woman who was treating a minor injury... And there are more and more similar cases. It would seem that these deaths have absolutely natural causes. However, Jack and Laurie believe that the deaths of patients are not accidental. Is there really a serial killer “working” in the hospital? Then on what basis does he choose victims? And what is his motive? The closer they get to the truth, the more danger they expose their own lives...