In the first episode we meet Mary Shannon a US Marshall for the Witness Protection Program. In this episode Mary tries to figure out what went wrong when a mobster's son who was under her protection is killed.

Things get complicated when Mary takes on the case of Leo Billups. Leo saw his mother murdered and is going to testify against the people who killed her including his father.

Mary's assignment this week is Treena Morris a con-artist who is married to a diamond smuggler. After she is arrested by the feds, she decides to tell all on her husband and his friends. While Mary is trying to keep her safe, Treena gets engaged and her photo is all over the papers.

Mary and Marshall take on a case involving Horst Vanderhoff, an agent for Lola, who's an assassin for hire. While trying to line up her next job, Horst is busted and agrees to testify against her to become a part of the Witness Protection Program.

Mary works to solve the mystery of who tried to kill her witness, an art dealer. To complicate matters, both his mistress and his wife are in the program…and key suspects.

Mary learns that her witness, a NCAA basketball star, has a gambling problem

The closeness of a family is tested when they enter the program after the daughter witnesses a shooting.

A member of the Program under Mary's watch is in a car accident and Mary has to find out if it was an accident or related to his former life.

Mary suffers the consequences when an attractive witness, who she slept with, is accused of murder.

Natasha, the mild mannered Ukrainian accountant, has gotten her new breasts, but her life becomes more complicated when she discovers that her new boyfriend is also in WITSEC.

After watching her mother audition for "Sweet Charity" Mary is kidnapped; in New Jersey, Brandi's boyfriend Chuck is abducted and two FBI agents are killed; when federal agents suspect a connection, a nationwide manhunt ensues.