In the season seven opener, a cop is shot in the line of duty and Detectives Robert Goren and Alexandra Eames race to the scene. Eames recognizes the victim: her husband's partner from the night he was murdered. It turns out that although the two murders were eight years apart, the only way to solve the current case is to reinvestigate her husband's murder as well.

A Park Avenue dentist's murder turns out to be connected to the death of one of his young patients. As detectives Goren and Eames look into both murders, they follow a trail of counterfeit and poisoned mouthwash from the streets of Harlem to the FDA and Wall Street.