Following the murder of Mr. Allen by The Mad Botanist using an African Tentacle Vine, the diabolical criminal targets the inventor’s partner, Mr. McCoy. FBI agent Veronica Darnell is assigned to protect McCoy by her superior.
Veronica goes to a premiere with McCoy. At the event, the botanist, disguised as Rose, the Broadway Flower Peddler, approaches the pair. McCoy permits the female impersonator to pin a Mediterranean Poison Cornflower on McCoy’s coat. McCoy is credulous and unaware of the impersonation and the dangers the flower poses until he begins to feel ill.
Captain Flag arrives and tells Veronica to get McCoy medical aid right away. The Captain pursues The Mad Botanist to the villain’s greenhouse. The Mad Botanist falls into a Man-Eating Clam Plant and is grotesquely consumed by it.