A doctor at a hospital diagnoses a woman with diphtheria and calls upon the hospital's virologist, Dr. Ross, to confirm the diagnosis. Ross begins to investigate the woman's background to determine how she contracted the disease, but his efforts are hindered by the police captain's focus on solving a separate case involving the murder of two police officers. As more patients are infected, Ross works to identify the source of the outbreak and enlists the help of a detective to aid in his investigation.
Killer by Night
A thrilling cat-and-mouse game ensues as a doctor and detective team up to combat a deadly epidemic and a ruthless killer, each with their own motivations and secrets.