In Los Angeles, Mary Walsh, a bank manager, takes her boyfriend, Kevin Peterson, to the County Memorial Hospital for an orthopedic surgery of ligaments of his left knee - an operation to be performed by Dr. Harding. Mary is a needy woman that has just lost her mother and started a relationship with Kevin four months ago. Mary meets Kevin, still wearing a brace on his left leg, in the preparation room of the hospital - nurse Amanda asks her to move to the waiting room. When Mary seeks information about the surgery, she finds that there is no record of Kevin in the system and he has vanished. Furthermore, Dr. Harding is on vacation and she can't locate a nurse Amanda on the staff lists. She calls the police and Detective Franklin is assigned to the case. No one believes Mary's story particularly when she accidentally drops her anti-depression pills on the floor, so she is sent to psychological evaluation with Dr. Markus Bensley that diagnoses her as unstable and delusional woman. Mary flees from his office and seeks out Kevin alone disclosing the truth about her prince charming.