Sheena's birthday party is rudely interrupted by a huge gray gorilla who attempts to kill Sheena's teacher Kali (Margo Moorer). "Something is very wrong", Sheena realizes. Kali has concealed from her that her former tribesmen were transformed years ago into animals... and stayed like that, so Kali is the last one of the tribe who kept human appearance. Sheena and Cutter follow Kali into the jungle, where they meet the gray gorilla and want to find out why he became a hateful rogue gorilla who made other animals attack villages. But when he turns back into his human form, things are getting worse...
Strange story, an attempt to take a step into creature horror with poor results. On the other hand, the character of Kali is deepened by a remarkable background story.