On the brink of summer vacation, the Dana girls receive a mysterious orchid. Dining out with ship captain Uncle Ned, they are accosted by a strange South American who asks to buy the flower and threatens them when they don't sell. Besides this there is a report from Uncle Ned that an insurance man is hunting for the trail of a biologist couple killed in the Brazilian jungles. Then at their camp the girls meet another pair of biologists, the Sterlings, who tell them of the black orchid sacred to a jungle tribe who do their best to murder anyone after it. In the showdown the mysterious stranger is revealed as the agent of the tribe and the Sterling's twins, the children of the lost couple. For this, serve some curare with your tea. It is all pretty wild.