 Daphne s Uncle John, a movie director, offers to put the kids into his current production, "The Ape Man of Forbidden Mountain." Uncle John needs all the help he can get, because everyone is quitting his movie. It seems that a local legend about an ape man is coming true, and is terrifying all the actors on the set. When the movie shuts down because the lead actress quits, the kids begin searching for the ape man causing all the havoc on the set.