A mysterious thief has been stealing groceries and other necessities from a suburban LA neighborhood. The only clue the thief has left behind are a couple of books on science and math. Following up the nameplate in one of the books, Friday (Jack Webb) and Smith (Ben Alexander) consult with college professor Winderman (Jack Diamond), who reveals the existence of a brilliant teenager named Peter Siler (Jack Diamond)--a misfit genius who has secluded himself in a cave in the Hollywood Hills. This episode was adapted from the Dragnet radio broadcast of July 12, 1955. ~ Hal Erickson, Rovi