Doc and Dick are cousins, but they are often called "The Tarzan Twins" because of they look very much alike. They are distant relatives of Tarzan's, and have been invited to spend their holidays with him. When they get lost in the jungle, they experience all kinds of adventurous situations: they are captured by a hostile tribe, seek shelter from a terrible storm and end up saving a missionary's daughter from the savages of Opar.
In order to prevent the crops from being destroyed by elephants, Mabu and Timai are appointed guards over the Meru tribe's plantations. The boys have to learn how to co-operate before they are able to kill the elephant.
