After Tarzan travels into the jungle to return a lion cub to his pride, and Jane and Roger go to the research facility. Dan is left at the camp by himself. While he does some handiwork around the tent, Dan is surprised to find his long lost twin brother, Joseph, standing before him. Joseph claims he need $10,000 immediately, or some people will come to collect the money or his life. when Dan refuses to cooperate, Joseph ties him up, takes his clothes, and drives off in the Jeep for Jane's research tent. When Joseph arrives, disguised as Dan, Jane and Roger notice his behavior is unusual. Joseph doesn't know hot to handle the reptiles, he can't fix Roger's Jeep; he simply isn't Dan. While Roger and Jane are willing to excuse "Dan's" odd behavior, Cheetah is convinced something is wrong. Although he notices Cheetah's outrage, Roger dismisses the chimp as having an off day, and works on the jeep engine with Joseph. Joseph ask Roger if he can somehow get $10,000, telling him he needs the money for "family problems." Roger talks to Jane, and they arrange for a $10,000 loan from their project's benefactor. Unfortunately, the benefactor says he needs a week to get the money and Joseph wants it immediately. When they arrive, Joseph has taken Roger hostage, and he races off in the Jeep. By the time Tarzan arrives, after releasing the Lion cub, Joseph is long gone. Tarzan makes a last ditch effort to catch up with the fleeing criminal. Back in the jungle, Joseph is stalled, when he finds a tree trunk road block in the middle of the road. The delay gives Tarzan just enough time to catch them. He swings across the clearing and kicks Joseph's gun from his hand. Tarzan captures Joseph and returns with Roger to camp. Now that the drama is over, Dan realizes that he needs to do more to resolve his troubled relationship with his brother. Tarzan tells Dan that sometime relative, like the lion cubs, need to be nursed to heath and returned to the confines of the family.