The discovery of nine human skulls leads Rush (Kathryn Morris) back to George Marks, the serial killer she was unable to incriminate months earlier, and who walked away a free man. As the detectives reinvestigate his mother's murder from 1972, George is forced to emerge from hiding to face Rush again. This time, their very lives are at stake in their final showdown.

When an old truck containing human bones is pulled from the Delaware River, the team re-opens the case of a missing and possibly murdered girl who disappeared unexpectedly in 1932.

A serial killer is to be released from a New Jersey prison based on a plea bargain made twenty-five years ago. Philadelphia homicide is asked to locate a potential crime committed while the killer was living in Philadelphia during the summer of 1977. A doorman was found strangled to death in a subway station in full uniform. The plot follows an evening at "The Rocky Horror Picture Show" involving the doorman, his girlfriend and the future serial killer. Valens received word from NYPD that his girlfriend was involved with credit card fraud and there's a warrant out for her arrest.

The murder case of a young mill worker is re-opened when Rush learns that a recent parolee admitted to stealing money off the victim's body.

The unsolved 1963 murder of a black teenager, whose body was discovered by the then-young Will Jeffries, is reopened.

A woman, who was romantically involved with Nick Vera in high school, claims that members of a fraternity might have been involved in her alcoholic sister's death in 1995. The victim's estranged husband and a bar owner are also viewed as potential suspects.

The 1982 murder of a Philadelphia socialite is reopened when her wedding ring is found at a crime scene.

Lt. Stillman's priest informs him of a long ago confession where a man confessed being involved in the 1998 kidnapping of a 9-year old boy. The case is reopened with this new lead, and it turns out the truth is closer to home.

When someone leaves drawings recreating an accident that killed a mentally disabled teen, it points the finger at the incident being murder.

Rush and the team investigate the 1969 murder of a 19-year-old girl whose body was found in her boyfriend's apartment the day he fled to Canada to avoid fighting in Vietnam.

After a murder weapon connected to the 1987 drive-by shooting of a little girl turns up, Det. Rush and her team re-open the case. The team slowly tracks back the gun's previous owners until the shocking original owner is finally revealed.

When a dying boxing referee makes a confession about a 1976 fight, the team re-opens the case in which an underdog fighter, arranged to fight against a much more qualified boxer, took a heavy beating in the match and died only moments afterwards.

The team re-opens the case of Matthew Adams, a teen-aged cult member who apparently committed suicide back in 1978, when his sister comes forth with new evidence about the deprogrammer her family hired to rescue her brother.

The team re-opens the 2000 case of a prominent Puerto Rican assistant district attorney when rumors about his connection to a large amount of money gone missing at the time of his death start to circulate. However, his widow insists that the claims are not true. The re-investigation reveals that the victim was prosecuting a murder trial and the man convicted for the crime after his death may possibly be innocent.

The headless torso of a woman who disappeared in 1985, on the same day she filed domestic-abuse charges against her husband, is found by hikers in a wildlife preserve. The investigation quickly leads to the grisly discovery of 8 more decapitated bodies, the victims of a serial killer.

The 1953 murder of a white school teacher, a communist sympathizer who was involved in civil-rights issues, is reopened after the victim's youngest son asks for it to be reinvestigated. The probe reveals that the slain man was killed on the same day that the Rosenbergs were executed and was set to testify the next day before the House Committee on Un-American Activities.

An HIV-positive gay man asks Rush and Valens to re-investigate the case of his dead partner who died of strangulation in 1983. Not only was the victim outspoken in his views about AIDS education within the 1980's secretive gay community, he was also the member of a very prominent family, disowned by his father for his sexual orientation.

Lilly reopens a 1990 murder case, in which a prep-school girl was found dead in a local swimming hole, after a present-day victim with similar markings is discovered at the same place. The investigation reveals that the victim of the earlier crime was routinely tormented by a trio of classmates who invited her to a sleepover the night she was killed.

Det. Rush investigates the 1991 double murder of married illegal immigrants from Cambodia who were shot to death in their apartment and found by their 6-year old daughter. The now-teenage girl brings the case to Lilly after she discovers a bracelet once owned by her mother is for sale on the internet. The probe reveals that the parents had dark secrets unknown to their daughter.

When human remains are found outside a former state prison, the team re-opens the 1968 case of a dead inmate, murdered on the night Johnny Cash's Folsom Prison Concert was broadcast to prisons throughout the country. However, when it's revealed that the bones don't belong to the person everyone had assumed, the team must start the probe anew by first identifying who the victim was.

Lilly and Valens reopen a presumed homicide from 1979 in which an unidentified victim's blood-drenched shoes, underwear and sheets were found in a trash bag, but no body. The investigation begins when a battered wife accuses her husband of murdering a girl in 1979 and brings in an amateur film from the time that supposedly shows him committing the crime.

On the eve of the 60-year reunion of women who worked in a weapons factory during World War II, Lilly is asked to re-investigate the death of Alice Miller, one of the worker girls. The death was deemed accidental at the time, but her friend pleads to Lilly to look closer into the case.

Lilly returns to her last case before joining the Cold Case Squad as she re-investigates the brutal triple homicide of a restaurant owner and his family, murdered in the restaurant bathroom in 2003. Also the other team member have personal reasons to closing the case; Jeffries grew up in the predominantly black neighborhood while Vera was the one assigned to the case when Det. Rush left.