After telling his mother, he wanted to leave school for good, seventeen year old Andy Deaver vanishes from his private boarding school, last seen by it's headmaster, Graham Spaulding.

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

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 .

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 She is eight-and-a-half months pregnant and, under the tight control of her husband Paul, has withdrawn from her family and friends.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.

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.

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 a priest disappears Jack begins to think that the man is involved in some wrongdoing rather than the possible victim of a crime.

A missing-persons case becomes a criminal investigation when, after a recently engaged woman disappears, it turns out that she was running a confidence scheme.

When a young soldier recently returned from Iraq disappears, Jack and Danny look into his disappearance only to learn that the soldier may have more secrets than they want to uncover.

The team searches for a man who goes missing after leaving his wife's hair salon to deposit the day's earnings following an argument with her. Meanwhile, Danny resists getting pulled back into the life of his convict brother who is up for parole, and Martin's impending firearms qualifications test dredges up unsettling memories for him.

The team Looks for a college football coach who goes missing after being fired for his role in the team's dismal season performance,but the investigation soon uncovers that the Coach new policy of suspending players who have academic and behavioral issues caused the football team to repeatedly play without its main players and suffer defeats due to this rule. As a result of this, The team begin to suspect that it was some of the angry players, or members of the school administration and even a high-stakes gambler who all are facing financial losses resulting from the teams losing streak. Meanwhile, Malone must make a difficult decision when his wife surprises him with her strong desire to relocate their family to Chicago, where she has just been offered a superb job opportunity

The team search for a nurses' aide who who disappeared from a rural road while changing a flat tire, only to discover that she is actually a fugitive wanted for the bombing of an abortion clinic.

Things with Jack and Maria's divorce are getting nastier as Maria's attorney forces Jack to relive not only his childhood traumas, but also throw his affair with Sam in his face and attack his dedication to his job.

Danny is skeptical when the pregnant girlfriend of his missing estranged brother, Rafael ""Rafi"" Alvarez, and mother of their 9-year-old son, tells him that Rafi has transformed himself into a responsible family man, who recently obtained a loan to open his own body shop. But Danny's investigation uncovers that Rafi has been seen with a convicted car thief, and the large sum of cash he'd been flaunting for his purchase of a body shop didn't come from the bank. Though Jack makes the point that Rafi may have legitimate explanations for the suspicious circumstances, Danny braces himself for the very real possibility that his brother may have put himself in harm's way.