In this second Carter mystery, a mysterious rash of cargo ships sinking in Panama leads insurers Llewellyns of London to hire vacationer Nick Carter and his eccentric associate Bartholomew to investigate. Nick recognizes influential nightclub owner Al Taurez as a shady operator, but getting the goods on him depends on slick diversions involving the heavyweight champ of the Pacific Tuna Fleet, a Panamanian bombshell armed with American slang, a young couple in love and a whole raft of crooks and cutthroats.

This final Carter film is a lot of fun, with Nick (unwillingly, at first) taking on a ring of Fifth Columnists (since this was filmed before the US entered the war, we're not told the villains are Nazis, but it's pretty clear anyway). Of course, the helpful and persistent Bartholomew is at his side--much to Nick's irritation. To further complicate things--and to make them still funnier--Joyce Compton is along for the ride too, as a delightfully brainless "detective" named Christine Cross.