Tough, sexy and smart Mary Shannon is a U.S. Marshal working for the Federal Witness Protection Program in Albuquerque, New Mexico. Life has only gotten more complicated for Mary as she tries to balance the demands of her job with her ever-stressful and emotionally draining family life. After the dust settles over the FBI ordeal and her traumatic kidnapping, Mary still has her hands full with a barrage of newly relocated witnesses. To help with her caseload, Mary relies on the support of her loyal, minutiae-obsessed partner, Marshall Mann, and her often ineffectual but well-meaning boss Stan McQueen. Further complicating Mary's life is the arrival of a new member to the WITSEC team, Eleanor Prince, an administrative assistant who manages to rub Mary the wrong way at every turn. At home, younger sister Brandi is pulling her life back together while Jinx faces her alcoholism for the first time. But Mary still can't decide how to deal with her on-again-off-again boyfriend Raphael.