Jill Young is a girl living on a ranch in rural Africa with her father. Jill buys a baby gorilla from some natives to keep as a pet. She names the gorilla Joe Young. Fast forward 15 years, and Jill is a young lady running the ranch by herself, as her father just died. Joe has grown into a giant gorilla, 3 times the size of a normal gorilla.
Max O'Hara is a nightclub promoter. He travels to Africa to capture animals for a new jungle themed nightclub he is planning. Gregg comes along to rope and trap the animals. They try to catch Joe, but he is much too strong. Joe is about to kill O'Hara, when Jill arrives and commands Joe to release him. O'Hara is amazed, and realizes that an immense gorilla taking commands from a beautiful lady will be a huge sensation. O'Hara hires Jill to bring Joe to America.
The show is a hit, and they are raking in the money. However, Joe is miserable, locked in a cage and away from Jill. Jill wants to take Joe back to Africa, but O'Hara won't let her. After one show, some drunk patrons sneak down to Joe's cage. They give show bottles of liquor, then burn him with cigars. An enraged drunk Joe goes on a rampage. He escapes his cage and destroys the nightclub, freeing lions and other wild animals. A court orders Joe to be killed as a dangerous animal.
O'Hara realizes what he has done to Joe, and decides to help Jill return Joe to Africa. O'Hara distracts the guards, while Gregg and Jill get Joe in a truck. O'Hara has a ship in the harbor to take Joe back. On the way to the harbor they pass a burning building. It is an orphanage, and there are children trapped on the high roof. Joe climbs up and down several times rescuing the children. Part of the building collapses on Joe, but the last child is safe in his outstretched arms. Joe is now a hero.
The movie ends with Joe living happily back on the ranch in Africa with Jill and Gregg.
Thanks Joseph C!