A shipping disaster in the 19th Century has stranded a man and woman in the wilds of Africa. The lady is pregnant, and gives birth to a son in their tree house. Soon after, a family of apes stumble across the house and in the ensuing panic, both parents are killed. A female ape takes the tiny boy as a replacement for her own dead infant, and raises him as her son. Twenty years later, Captaine Phillippe D'Arnot discovers the man who thinks he is an ape.