Recovered from the shooting, Lilly wants to convince her boss that she's ready to get back to work. The team re-opens the 1994 case of three 10-year-old kids who were beaten to death when Lilly suspects the teens convicted of the killings may have been wrongfully incarcerated.

In the fourth season finale, a hostage situation arises when the entire team is held captive while they're investigating the 2006 killings of a family who had just moved into a new house.

The 1998 death of a terminally ill man who died months before he was expected to is investigated after a nurse confesses to six so-called mercy killings.

The 2005 murder of a longshoreman who accidentally became involved in a human-trafficking ring run by the Russian mob.

The team re-investigates their oldest cold case yet, the 1919 murder of a young woman who was a passionate advocate for women's right to vote.

The 1997 murder of a 16-year-old girl high-school cheerleader is investigated after an anonymous confession is discovered in a modern-art exhibit.

A father pushes a registered sex offender off of a building and threatens to kill a different sex offender each day until the cold-case unit solves his son's 1987 rape and murder.

The 1999 murder of a homeless woman, whose body is found at the bottom of a river in a station wagon, is investigated.

When a body is found in a dumpster, the team re-opens the 1984 case of a murdered teenage boy who wanted to become a dancer against his father's wishes.

Lilly investigates the 1964 murder of a 17-year-old girl who was sent by her parents to a home for unwed mothers, where she gave birth to a girl. The next day the teen was killed. The case is reopened when the victim's daughter comes forward, having just learned that she was adopted and that her biological mother was slain.