A serial rapist sends a letter to the squad announcing his return to Philadelphia after five years and his plan to strike again. Lilly's best hope of catching the rapist comes from a victim who is able to provide a composite sketch.

A college professor (Jeffrey Nordling), who lost everything − his career, his family, his reputation − after being suspected of murdering one of his female students (Kaitlin Doubleday) in 1995, offers new information regarding the case that he hopes will clear his name. He believes the student's death is connected to a copycat murder of a prostitute. Rush investigates the woman who was killed and the men in her life in order to discover which one of them killed her.

The team reopens the 1985 case of a wealthy stock broker. At the time it was deemed that Charles Danville was killed when someone attempted to steal his car, but new evidence suggests that he may, in fact, have been murdered.