After a wealthy middle-aged man is murdered in the elevator of his Park Avenue apartment building, the team must track the only witness to the crime who fled the scene.

After a wealthy man is shot at close range in an elevator just outside of his penthouse apartment, Mac and Det. Flack realize that a companion may have witnessed the murder. Their investigation leads Danny and Lindsay into the world of underage high school girls who disguise their age and revel in the Manhattan social scene in order to meet wealthy men. Meanwhile, Stella and Dr. Hawkes investigate the death of a seemingly well-off young man found in a Central Park lake who seems to have two identities.