Kadence, a new type of implanted defibrillator, misfires in a patient visiting University Hospital for a routine medical procedure. Dr. Kate Downey, an experienced anesthesiologist, resuscitates the patient, but she grows concerned for a loved one who recently received the same device --- her beloved Great-Aunt Irm. When a second device misfires, Kate turns to Nikki Yarborough, her friend and Aunt Irm’s cardiologist. Though Nikki helps protect Kate’s aunt, she is prevented from alerting other patients by the corporate greed of her department chairman. As the inventor of the device and part owner of MDI, the company he formed to commercialize it, he claims that the device misfires are due to a soon-to-be-corrected software bug. Kate learns his claim is false.

When her elderly patients start dying at home days after minor surgery, anesthesiologist Dr. Kate Downey wants to know why. Surgeon Charles Ricken places the blame squarely on her shoulders. Kate is currently on probation and must prove her innocence to save her career. Aided by her eccentric Great Aunt Irm, a precocious medical student, and the lawyer son of a victim, Kate launches her own unorthodox investigation. As she comes closer to exposing the culprit’s identity, she faces professional intimidation, threats to her life, a home invasion, and the suspicious death of someone close to her. The stakes escalate to the breaking point when Kate is forced to choose which of her loved ones to save --- and which must be sacrificed.