Assigned to Juvenile Bureau. A destructive teenager needs to be stopped from vandalizing the city, and it’s up to Joe Friday to stop him.

On the streets, Joe and Ben interview the latest victim, where details of the break in are told. Checking in at schools, Joe hopes to turn up kids who are known for malicious pranks. Still without much in the way of leads, it’s back to the streets. Checking trash for paint cans, nothing turns up to match the vandalizing.

A lucky break leads Joe and Ben to a timid mom. Is her son involved with the paint,, or the other damage?

Out of the blue, a teen ager enters, wanting to confess. Arnold Waterman claims to have shot a man, but there’s no body. Did he really do it? Mom arrives to tell about her son’s pathological lieing, but one of his lies link him to the spree of vandalizing.