“Dragnet” returns with a tale of the drug trade. In 1951 marijuana was available for 75 cents a joint. Detectives Friday and Romero are on the track of the kingpin behind the narcotics racket, “The Big Tomato.” Then Friday himself, Jack Webb, guest stars on “The Bob Hope Show.” After Hope’s timely comedy monologue, he joins Sgt. Joe Friday in a homicide investigation. Even if the only stiff Bob’s ever seen stretched out was one on New Year’s Eve, with a nose like his, you bet he can smell a crime a mile away.