Mary Shannon is a U.S. Marshal in the witness protection program who spends her time relocating federal witnesses.. Based in Albuquerque, New Mexico, Mary works with her partner, Marshall Mann, to place criminals and innocent witnesses into new lives. When not putting her life on the line to protect federal witnesses, Mary attempts to manage her dysfunctional family, including overly dependent mother, Jinx, and younger sister, Brandi, both of whom live with her.