The Valley of Gwangi

Somewhere south of the Rio Grande at the beginning of the century, Champ Connors is the owner of a huge open air circus that presents remarkable shows as well as historical battle reconstructions between cowboys and Indians. Among the artists, Diana, performs in a particularly difficult show. Tuck Kirby, has left the enterprise to work as a free-lance agent and sells shows to famous characters like "Buffalo Bill".

When he returns to Connors's circus, it is to propose that Diana work with him. She refuses because she has found a new attraction that will make her a celebrity. Unable to hide her secret any longer, she shows "El Diablo" to her past fiance. It concerns a Eohippus, a kind of tiny horse that existed about fifty millions years ago...