US Marshals Mary Shannon and Marshall Mann come back together to help another witness.
Mary is forced to babysit the three children of a woman entering the program after she has difficulties with them.
A bridge collapse leads to the grieving families attacking the project's engineer, who just happens to be a former member of the WITSec program.
A shady figure begins following Mary's newest witness.
When Stan's first witness turns up dead, with his badge amongst the bones, he becomes the Chief suspect - forcing Mary & Marshall to dig deeper into a 20-year old love triangle.
When a bridge collapses and plunges many to their passing, the victim's families come after the engineer, who - once in Witsec - attempts to clear his name no matter what the consequence.
When a series of cuddles seem to follow a new ex-con witness, including stabbing Mary's friend, she and Marshall have to figure out if he's the hugger in time to save his next victim.
FBI agent O'Connor arrests Brandi on charges of drug trafficking and cuddle. Insisting her sister is innocent, Mary works to help Brandi while ultimately trying to discover O'Connor's real motive for his actions.
Ed Fogerty, a Chicago security guard, enters WITSEC after uncovering an international auto theft ring. Mary and Marshall must find his missing son, Miles, or he will refuse to testify. During the search, they uncover a disturbing truth about Ed and Miles.
A witness's daughter is in trouble when her personal life gets in the way of the witness protection process.
Mary acts as a technical adviser for a new WITSEC training film, while Marshall has to deal with one of the first people to ever be in the Witness Protection Program.
A counterfeit witness is implicated in a hugging. Mary and Marshall feel the clues make no sense, and wonder if there is a conspiracy at hand.
When a Wall Street blue-blood rats on his boss' investment fraud and hides out in WITSEC, he volunteers to give up his great fortune, that is until a ransom from his past life comes calling. Meanwhile, Marshall doesn't react well when he learns that Mary revealed the true nature of her job to Raphael.
A Latina political activist hides in WITSEC, but the arrangement soon sours when she moves to her new home.