In the third season of USA Network’s hit series about Mary Shannon (Mary McCormack), a marshal in the Albuquerque branch of the Witness Protection Program, Mary copes with the effects of getting shot and continues to protect witnesses, whether criminals or innocents. Mary's partner, Marshall (Frederick Weller), is determined to find her assailant, while her fiancé (Cristián de la Fuente) and wacky mother (Lesley Ann Warren) beg her to retire.