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.

The family regroups after Mary's ordeal; Stan and Marshall search for a way to force Spanky to tell the truth about Chuck's drug trafficking; the FBI corners Mary in her driveway with Brandi's suitcase full of meth in the back of her car. Season 1 Finale

Mary uses a thief to catch a thief when she asks a witness to consult on a crime in order to exonerate Brandi of grand theft auto.

Mary's paranoid witness wants to reconnect with his son.

Mary is caught between a witness and a suspect.

A beauty pageant queen finds out that she's spent most of her life in witness protection

Mary works with an unapologetic con artist.

An Amish witness comes into the program and must learn to adapt.

A terminally ill father wants to reconcile with his children.

Mary plays marriage councilor in order to mediate a WITSEC divorce. Not only must she reconcile a stubborn witness, but also thousands of years of Hindu tradition, in order to save the case and keep a family out of danger.

Mary gets a WITSEC two-fer, when a witness is forced to enter the program after being mistaken for his "evil" twin brother. Not only must she protect the pair from their enemies, but also from each other.

Marshall and Stan contend with a rock-star witness and her controlling mother while Mary is away on a WITSEC-mandated road trip.

Mary helps protect a guilt-ridden Army veteran; Marshall & Abigail consider the next step.

Mary protects a courtesan from the gangster father of her baby.

Mary must protect her least favorite witnesses on the day of her sister's wedding.

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 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.

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

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

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.