Frank and Joe Hardy investigate the mysterious disappearance of a champion race horse, a case that leads the teenage sleuths on a pursuit of a desperate and murderous villain.
The Hardy Boys stumble across a twisted technological plot creating perfect replicas of human beings and fight for the survival of a top secret government intelligence organization.
In trying to free their friend Holly from the clutches of a murderous mountain cult, the Hardy Boys find that the lunatic Rajah and his followers have spread to their own home town.