Patrick Kent, a Vice-President of a New York investment-banking firm, vanishes from a San Diego airport, only leaving behind two empty suitcases.

Abby, the three-year-old daughter of ADA Angela Buckman and her NYU lecturer husband Matthew, vanishes while in the park with her nanny.

After a confrontation with a local bully, foster teen William Hope disappears leaving his job at a burger restaurant late at night.

Third-year-resident Anwar Samir vanishes from the hospital he works in. Because of his Saudi-Arabian background, suspicions of terrorist links arise.

When a man leaves his home in the morning with his daughter to take her to school and then to open his dry-cleaning store, but they both of they never make it there .

Annie Miller disappears on her way to school. The group looks into her disappearance, with their suspects ranging from the local mayor, to Annie's godfather, all the way to a young man working for the father of her best friend. Twenty-four hours after Annie's disappearance, her best friend Siobhan Arintero also vanishes, leaving only a collection of videos to help find the two girls.

Jack and the team search for a pregnant woman, Kathy Dobson, who disappeared from a hospital before being told that she has serious complications. As the detectives race against time to find Kathy, their investigation gradually reveals that Kathy's seemingly happy life actually hasn't been going very well. She is eight-and-a-half months pregnant and, under the tight control of her husband Paul, has withdrawn from her family and friends. Paul's brother Ritchie, who has been following Kathy and providing Paul with addresses she visits, lists a woman who may be affiliated with an ""underground railroad"" that helps battered women. When the team members find the woman, they learn that she has been assaulted by Paul—but she still refuses to lead them to Kathy.

Chet Collins has been searching for his son since the boy was kidnapped four years earlier on a camping trip, and is the one case that Jack has never been able to forget. When Chet disappears, leaving behind only his wedding ring and the mountains of debt he had accumulated in his search, Jack will go to any lengths to find Collins and save him from himself.

The team investigate a disappearance of a flight attendant who may have been having a relationship with one of the pilot's.

A bride disappears at her own wedding and suspicions of kidnapping. Meanwhile, the team explores the relationship between the newlyweds, who were lived together for a little while.

A girl vanishes from a psychiatric hospital, and it appears she may have escaped with a staff member. Then the team learns of a troubling incident from her past that may hold the key to her disappearance.

They search for a retired U.S. Army officer who has disappeared right after a dinner that was given in his honor by former members of his Vietnam platoon

Delia , a television reporter, disappears in the middle of the investigation of a nightclub owner who is a suspected drug dealer. They also discovers that Delia was working on the case of a murderer on death row who she thought was innocent, and who might be linked to an assistant district attorney working with Jack on the case.

They search for a young high-school teacher who disappeared after a night class in the Bronx, turning up contradictory information about the subject.

The team find themselves up against the ropes as multiple mysteries arise in the case of a boxer. Dante Jones disappears moments before a bout with a $500,000 purse that which could have made him a title contender. Jack suspects it's stunt, but Vivian, a Jones fan, can't believe that the charity-loving, straight-arrow fighter would go doewn that low road. The search goes in a new direction when his younger brother who he is always bailing out of trouble, vanishes. Then it's learned he has made 2 million dollers in the past five years,but he only has $6000 in his bank account.

Jack's methods for investigation of child molester could result in the case being kicked out of court. Then on top of that, the Office of Professional Responsibility decides to investigate the team, but their real target is Jack

With the aftershocks of Sept. 11 and man named Barry , who lost his wife that day and then his job soon after. The man lashes out at her former boss an employment-agency owner. Blaming her for his wife's death and his own failure to find a job, Barry kidnaps the woman for ransom.Then he demands the money be exchanged at a bookstore, but when the cash is delivers Berry is provoked and takes the store's patrons hostage. Among them is Samantha,and given Jack's affection for her complicates the negotiations.

When the team tries to plot a strategy after they find out that Samantha has been shot and that she might be critically injured in the hostage crisis situation. Jack makes a deal with Berry so that Sam can get help and Jack goes in there and takes Sam's place.