Mary is placed on administrative leave pending the investigation of the FBI's raid on her house at the conclusion of the previous season. (The FBI unsuccessfully searched Mary's house for the drugs that her sister Brandi was holding for Brandi's boyfriend, Chuck.) While on leave, Mary's cases are given to Marshall, but Mary is allowed to work unofficially -- as Marshall's deputy -- when one of Mary's witnesses, who had been taken into the program 17 years earlier, dies under mysterious circumstances.