A low-rent Robby the Robot is at the center of this demented series entry starring the villainous Dr. Krupp (Luis Aceves Castañeda), a.k.a. The Bat. It's an entry but not an exit from the mummy mania that began with The Aztec Mummy followed quickly by The Curse of the Aztec Mummy. If you haven't seen those embalmed masterworks, no need to worry-nearly half of this tertiary treat is made from footage from its predecessors, so you'll get a whirlwind tour through tombs past. Evil Dr. Krupp is back and battier than ever in his efforts to steal the sacred Aztec breastplate from the chest of Popoca, a reanimated stiff. To defeat his formaldehyde foe, The Bat builds a robot, “the relentless machine,” that looks like a garbage can with a picture window and a human head peeking out. Not to be overlooked is foxy Flora (Rosita Arenas), the reincarnation of a long dead Aztec princess who was Popoca's pre-Columbian paramour. Aztec or not, it's just another pyramid scheme.