Pediatrician Erica Rosen is stymied when two of her patients don't respond to medicine as expected. When other patients later develop strange, unexpected illnesses, she is determined to get to the bottom of it.

Meanwhile, the department's newest pediatrician, Dr. Nilsen, appears to be trying to steal her patients. Erica suspects he is after her job as the clinic director. She also discovers Dr. Nilsen has become romantically involved with her trusted assistant, Martha. One evening, while looking for patient information on Martha's desk, Erica comes across a list with the names of some of her patients. A boy who recently became ill with a mysterious malady is on the list and has an asterisk by his name. What does that mean?

Erica is convinced something nefarious is underfoot, and Dr. Nilsen, rather than simply being after her job, is engaged in a dangerous scheme involving her patients. Unable to recruit the help of law enforcement in a timely manner, she realizes she must take matters into her own hands. As she proceeds with her investigation, she is unaware of the dangers she is about to encounter.