The latest number the machine dispenses belongs to heart surgeon, Dr. Madeleine Enright, known as the best in her field. That is why wealthy businessman Oliver Veldt chooses her for his heart surgery, which is kept secret from the public and for which the entire wing of the hospital is to be kept secure for his safety. Finch and Reese are certain that she is the intended target. But they quickly learn that she is the unwilling perpetrator. Just before the operation is scheduled to begin, she is threatened by a mysterious Brit named Alistair Wesley to kill Veldt on the operating room table and make it look like an accident, or else Wesley will get one of his many operatives to kill Maddy's wife, Amy, who, during the duration of the operation, is left vulnerable in a wide open and busy public space, where the many unknown operatives can monitor her movements. Reese and Finch also learn that Wesley has at least one operative somewhere in the hospital monitoring what Maddy is doing in the operating room. With the help of one of their old persons of interest who again is in trouble due to his own doing, Reese and Finch have to find out for who Wesley is working to discover why he is intent of killing Veldt before Maddy has to make the decision to sacrifice Veldt or possibly her wife Amy. Meanwhile, Fusco calls in Carter on a homicide that seems to have a personal connection to her.