A promiscuous teacher at a school deep in the mountains is stabbed to death with a pair of scissors. Betty, an old friend of the victim, goes up to investigate. The victim was so disliked because of her ways that Betty reaches a stone wall. Betty realizes that the dead teacher was mentoring an autistic young girl, who never speaks. Evidence from the dead teacher's final walk leads Betty to believe the girl was with her and witnessed the murder. The unseen killer knows it too, and is a crazed maniac who chases the girl out into traffic. Betty calls Barnaby and J.R. for help while trying to see if the child will somehow break through and say something about the crime. Journalist Carolyn See and actress Jackie Joseph wrote the script (their only screenwriting venture), and See described the making of the episode in a TV Guide article the week the show aired.