More Puppet Master horror. Eric Weiss (Jacob Witkin), the boy from Puppet Master III, is now grown up and has become the Puppet Master. He has spent his life trying to perfect Toulon's secret of giving life to the inanimate. But now he is confronted by Maclain (Kate Orsini), a rogue agent who wants to peddle the secret on the open market and breaks into Weiss' lab. When Weiss refuses to give up the secret, Maclain tortures him and threatens to kill him. But are the puppets ready to spill blood for their master once again? The film intersperses new footage with flashbacks to previous Puppet Master films.