Brandi's wedding day has finally arrived, & Mary finds herself torn between two duties: job & family. The one day of the year she can't be at work, Maid of Honour Mary is called in to testify about her role in the sting on arms dealer Julian Conran, & she can only hope to get to the courthouse & the church (or in this case, the country club) on time. Complicating matters is the fact that Mary is confronted with two rather unwelcome visitors: her ex-husband (and baby daddy) Mark, & Ronnie Dalembert/ Mc Intyre – the con man Mary met & detested only a few months earlier. While Mark comes through for Mary, Ronnie manages to screw things up for everyone yet again. Only this time, things get really ugly for the Wit Sec team when, while escorting Ronnie to give his testimony, Mary, Marshall, Stan & Delia find themselves trapped in the courthouse & ambushed by assassins. ...

Mary's new witness Adam Wilson is blowing the whistle on his boss, a well-connected military contractor, & the stress is taking a toll on Adam's psychological health. When Adam's paranoia & hallucinations worsen, Mary & Marshall realise their witness might have gone off the deep end. But as they attempt to get Adam back to dry land & protect his justifiably alarmed teenage son Joey, Mary & Marshall begin to wonder if there might be some truth behind Adam's wild claims. After all, just because you're crazy doesn't mean they aren't after you. ...

Love is in the air in Albuquerque, as Mary is forced to tend to a lovesick witness pining for his childhood sweetheart. When Jimmy Hart finds out the au pair company he's been working for is actually a front for a human trafficking ring, he's appalled—and ready to testify, no matter the personal cost. But when he learns that prosecutors are trying to build a case against Winnie, his lifelong best friend & crush, Jimmy stonewalls. He'd rather go down himself than hang her out to dry. ...

Mary is surprised to get a call from longtime witness Sharon Harris, a drug dealer-turned-devoted-PTA mom who's stayed out of trouble for years. & when she meets Sharon, Mary is in for two unpleasant new surprises: one, there are no homemade cookies in sight; & two, Sharon's teenage daughter Beth has somehow gotten her hands on her mom's old mugshot & is about to unravel the truth about Sharon's past. ...

When Mary busts Marshall's witness Ronnie Mc Intire, an allegedly reformed con man accused of bilking money from unsuspecting seniors, she's hoping to get him kicked out of the programme & packed off to prison. Unfortunately for Mary, the FBI is onto Ronnie too, & they're eager to take advantage of his access to notorious arms trafficker Julian Conran. Since Conran happens to have a thing for busty blondes, Mary soon finds herself strapped into a push-up bra & going undercover in an effort to protect Ronnie & get the goods on Conran. While Mary might have been able to see through Ronnie's lies from day one, when her ex-husband Mark shows up at her door her feelings are less clear. ...

If there's one thing witnesses & Wit Sec inspectors share, it's daddy issues. Or so Mary & Marshall realise when they meet witness Ben Kulpak. Angry with their father for the mistakes that landed him in this mess, his grown kids refuse to come into the programme with him. But when Ben winds up in the hospital & the Lithuanian mobsters after him manage to track down his kids, everyone's plans change. Tom & Cecile agree to join the programme & soon arrive in Albuquerque, but unfortunately it's a less than joyous family reunion — in part because there's some deserved resentment on their side for his wrongs as a father, & in part because it turns out that Ben has another secret he's trying to keep from his kids: he's dying. ...

When Dr. Amit Kishore, a well-respected neurosurgeon, runs afoul of the law by conspiring with the Indian mob to commit Medicare fraud, he cuts a deal & enters Witness Protection with his family. Unfortunately, the now-Kumars are not exactly one big happy family, & not long after their arrival in Albuquerque, the formerly docile Mrs. Kumar makes a shocking request: a divorce. Things get messy for the Wit Sec team when Ashok & Sudha (as they're now known) battle over the children, & an arrogant U.S. Attorney with a grudge against Stan pressures the team to keep the feuding couple under control. Though Mary & Marshall do their best to help the Kumars find common ground, it's anyone's guess as to how this story will end. After all, as Mary knows better than anyone, life is full of surprises: sometimes you get to start over, & sometimes you get pregnant. ...

It's a story as old as time, or at least as old as the story of Cain & Abel: two brothers turn out as different as can be, & can't seem to find a way to get along. Throw in a connection to an inter-state fraud operation, an FBI bust, & a subsequent relocation to Albuquerque, & you've got family drama of Biblical proportions. Meet George & Billy Stone. George is fastidious, Billy is fast-living. George is upstanding & responsible. Billy is... a mess. & now, thanks to Billy's involvement with some unsavory counterfeiters & a case of mistaken identity, both brothers have been dropped in Mary & Marshall's backyard. Billy adores his brother & is desperate to stay together; George's feelings towards his ne'er-do-well younger sibling are less warm. Even if Mary & Marshall can keep the brothers from killing each other, they've still got the angry thugs back in California to worry about. ...

With Mark co-parenting, Jinx playing babysitter & Brandi day-trading with their half-brother in Florida, Mary is finally ready to return to work for the first time since having baby Norah six months ago. WITSEC's latest witness is Ivan Gunter, a college student & a member of an elite eating club that runs a gambling website. When Ivan witnesses Brockton Jr., the president of the eating club, murder a fellow member, Ivan knows that he & his mother are in serious danger & in need of WITSEC's help. ...

With Jinx out of town & Mark busy with a last minute business trip, Mary has no choice but to head to work with Norah in tow. But when Mary arrives, Delia points out the obvious: Mary can't be with Norah & a witness at the same time. Fortunately, as Mary soon learns, Delia, Stan & Marshall make pretty good babysitters. Mary's first meeting of the day is with Beth Wilcox, a doll collector who entered the programme five years ago. Beth's landlord has been threatening to post a video of her on the Internet, which Beth & Mary both know could be a problem for Beth. Mary sends Delia to evaluate the situation at Beth's apartment so that she can check in on Carlos Ramirez, an alpaca farmer, who is worried someone from his previous life may have spotted him in town. ...