When famous detective Nick Carter visits Prague, he becomes involved in strange case of a missing dog and even stranger carnivorous plant. He becomes convinced that he is standing against his greatest enemy, the Gardener, who supposedly died years ago in a swamp...
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.
Detective Nick Carter is brought in to foil spies at the Radex Airplane Factory, where a new fighter plane is under manufacture.
A secret agent uncovers four atomic rockets with a lethal gas warhead which have been stolen from a secret factory, and a dastardly plot.
Didier Formenter, the French scientist, has just put the final touch on an invention that will be able to destroy to destroy any sort of flying apparatus. An international crime gang is very interested in stealing this equipement to sell it to the higher bidder of lawless nations. Menaced, the scientist, who was friends with Nick Carter's father, calls Nick for help. At Nice airport, Nick Carter escapes death, but that night he is unable to stop Formenter's murder. He suspects Bruno, Formenter's adoptive son, and Tonio, the owner of a bar near Formentier's home. Bruno is actually after Formenter's heritage, and for that he tries to kill Catherine, Formentier's granddaughter. Therefore, Nick Carter finds himself against more than a gang, but he will uncover the plots, in time to break every gangster apart.