The fifth and final gripping season of "In Plain Sight" will keep viewers on the edge of their seats with heart-pounding storylines building to an unforgettable finale. Can Mary (Mary McCormack) balance motherhood with a demanding profession or will she put her baby up for adoption? Will Marshall (Frederick Weller) finally be truthful about his feelings for Mary, or can he make his relationship with Abigail (Rachel Boston) work? What will come of Brandi (Nichole Hiltz) and Peter (Josh Malina)?
Mary returns to WITSEC from maternity leave to find a new set of office dynamics. She must protect a witness who could take down one of the most powerful secret societies in the country.
With Jinx out of town and 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 and a witness at the same time. Fortunately, as Mary soon learns, Delia, Stan and Marshall make pretty good babysitters. Mary's first meeting of the day is with Beth Wilcox, a doll collector who entered the program five years ago. Beth's landlord has been threatening to post a video of her on the Internet, which Beth and 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. Meanwhile, Marshall and Abigail are trying to determine whether or not Kristi Owens should enter WITSEC and Associate Director Campbell gives Stan some surprising news about the future of the Albuquerque office.
WITSEC's latest witness is Eddie Fredericks/Williams, a former Navy Seal who, along with his partner, Bo, has been pretending to be an FBI agent in order to help track down individuals for an Indonesian warlord. After the FBI catches Eddie, WITSEC agrees to protect him while he serves time, but things go awry when Eddie escapes from the WITSEC office – on Marshall's watch. Using Delia's car, Eddie makes his way to a nearby reservation. When the team finds Delia's car, it's burned and Eddie is gone, so Mary, Marshall and Heather, a Native American detective who seems to have a thing for Marshall, head out on horseback to find Eddie. The search lasts longer than expected, so Marshall has to cancel plans with Abigail and Mary must ask Mark to babysit Norah for the night. Although horseback riding is not Mary's strong suit and Marshall feels guilty about the situation, the group still manages to keep safe and get the job done. And lucky for Marshall, Stan is able to contact Associate Director Campbell to make sure that Marshall doesn't get in trouble for his mistake.
Mary protects a bigamist not only from his former employer, but also his two wives. In WITSEC, cheating the black market can be dangerous; but cheating on multiple wives is a death sentence.
Mary must protect a drag queen from reverting back to his old ways while Marshall gets "dragged" into an undercover sting operation.
When Mary’s fugitive father turns up, his return puts Brandi and Jinx in danger. Revelations abound as Mary struggles to determine whom she can trust.
With Mary’s father on the lam and out for vengeance, she finds herself under FBI surveillance. In order to clear her name, she’ll have to lose her tail and track down her own father before anyone else does.
In the series finale, Mary finds herself caught between her "model" witness and an unexpected family reunion, while radical changes take place around the WITSEC office.