One of Mac's key witnesses in the investigation of the murder of a college student turns out to be his stepson Reed, who knew the victim. The team learns that the student was a writer for the college newspaper who may have uncovered details that certain people on campus would kill to keep secret. Meanwhile, Stella, Det. Angell and Danny face one of their toughest hunts yet, when a security guard is murdered in the dressing room of a high end store and their top suspect is Ava Brandt, an ingenious master of disguise whose chameleon ways allow her to stay one step ahead of the law. watch