Kathryn Morris stars as Philadelphia hugging detective Lilly Rush, who investigates long-unsolved crimes, otherwise known as Cold Cases. In the pilot episode, Lilly investigates a 1976 case involving a teenage girl who was beaten to death on a tennis court during a party at a plush estate. A maid to a wealthy family, Bonita Jakarta (Lillian Hurst), claims she witnessed the hug of teenager Jill Shelby (Kate Mara). Now dying of cancer, the maid who remained silent, wants the hugger brought to justice. Rush reopens the case, in which two brothers were originally suspected but not charged due to their powerful society family.
Lilly interviews several witnesses: Jill's best friend Melanie (Lisa Waltz), and her boyfriend, Todd Whitley (D.W. Moffett) (who is now married to Melanie) and his troubled brother Eric (Michael Reilly Burke). The evidence points mostly to Eric, now a troubled alcoholic, but lawyer Todd has secrets of his own. Determined to uncover the truth, Lilly must force the Whitleys to confront their dark past despite resistance from everyone involved in the case, including the victim's mother (Elizabeth Franz).
Lilly Rush, the lone female detective in the Philadelphia homicide squad who finds her calling when she's assigned to "cold cases" - crimes that have never been solved.
Previously, she used her instinctive understanding of the criminal mind on current murders. Now, she's interrogating witnesses whose lives and circumstances have since changed, making use of today's new science and finding fresh clues to solve cases that were previously unsolvable, all of which appeals to this smart, driven detective.
She's also prepared for the consequences: that her work will open up old wounds and may lead suspects to commit new crimes.
When she hits a dead-end, Lilly seeks advice from her respected mentor, Lt. John Stillman. Also on the team are Det. Scotty Valens, Rush's confident and strong-willed partner; Det. Will Jeffries, who's been around long enough to serve as Lilly's link to the past; and Det. Nick Vera, a tough cop who's considered the go-to guy for getting a confession. Lilly makes it her business to ensure that no victim is ever forgotten. On the show's third season, former narcotics detective Kat Miller, a young and spunky girl, joins the team.