Dr. Astin's wife picks up a young boy looking for a ride one night, and then they are both injured in an automobile accident. She and the boy are taken to the ER, and Astin's wife is assumed to be the mother of the child. She is unconscious for awhile and cannot correct the hospital's false impression. Quincy comes to visit, and while there, notices large bruises on the boy's back that were not caused by the accident. There are also signs of bones that have been repeatedly broken and have healed unaided. This leads Quincy to believe the boy is a victim of child abuse.
He is warned to drop it. Nobody wants to be "the bad guy" and start accusing the parents with no witnesses. The boy won't talk - and by that I mean AT ALL. Quincy goes around the boy's neighborhood asking neighbors if they have seen any abuse. Nobody but one rather randy neighbor who fancies Quincy will say anything. When the boy runs away from home, Quincy doesn't call the parents but lets him stay on his boat overnight. He's lucky he's not the one going to jail. How does this all work out? Watch and find out.
This was one of the first Quincy message episodes - it might have been THE first - and it was done with considerably more finesse than the message episodes in seasons seven and eight. That being a low bar by the way. This was made right about the time that more attention was paid to possible physical abuse committed by parents. I do remember that by the 80s there was considerable visibility concerning the issue.