A 100 year-old scientist stays alive by blood transfusions from unwilling young women until he's caught and executed, vowing his descendants will take revenge. Seventy years later, his great great grandson digs him up and brings him back to life and there's two nuts for the price of one until the old guy imprisons the young one and takes his place...
There's a church, a priest, a bible, and icons of Jesus on the cross amid all the appropriate trope such as graveyard crypts, laboratories, coffins, bats, and ageing in an instant but instead of the Universal horror films many of these Mexican movies resemble, this one's AIP all the way. Because the women don't die (they're just locked up to be used again and again), there's basically a zero body count until the end's just desserts but it could have been worse; I saw the original subtitled version and not schlockmeister Jerry Warren's dubbed abomination reconfigured for U.S. drive-in consumption. Leading man Fernando Casanova (great name) in a dual role looks like a cross between Desi Arnaz and Robert Wagner.
It's alright, I guess, but nothing to get excited about let alone recommend.