Assigned to narcotics detail, Joe Friday has to find the source of the steady flow of drugs into the city. The story begins in the interview room where Friday and Smith talk with a young man who has been picked up in possession of marijuana. Of course it isn’t his, but Friday doesn’t believe it. Unfortunately, there’s nothing more to be learned, so Joe and Frank track down other sources of information.
Word from the street comes in about a big shipment. Who is involved? How can the cops nab them? The best way is for Friday to go undercover and join them. Since all the informants are playing it tight lipped, Joe begins to set up his cover as an out of town buyer. It pays off, and Friday is to make contact to make a deal.
Things begin to take a bad turn when, although Joe has Frank stand by to close in, the drug dealer recognizes Joe. Uh-oh. Time to act fast before somebody gets hurt.
Fortunately, Frank swoops in, and the drugs and dealers are taken in. As big as these fish are, will they turn on the man who supplies them?