Really, this subpar film from the Universal stable of horror films, was actually a love story. The dwarf was in prison with Dr. Naish (Karloff), who with chalk in hand, scrawls strange formulae on his prison walls, such stuff as the atomic formula for the bomb, stuff like that. Suddenly, a giant lightning bolt hits the prison and most of it falls apart! Don't make 'em like they used to.
Karloff in the person of the not so good doctor and his dwarf (who calls him 'master' for some reason) capture a carnival wagon which claims to have the original Dracula inside. As a subplot, the doctor wants his revenge on the people who put him in prison, using the monsters to carry out this revenge. Dracula dies by sunlight, even his clothes disappear until all that's left is bones, bones and more bones. John Carradine was pretty good as the dapper Dracula, posing as a Baron from Transylvania.
The dwarf falls for a dancing gypsy girl, but she eventually dumps him for Larry Talbot, who still is tortured by the full moon and that fact that he can't help but tear out bloody throats with his bare teeth.
The film is a bit slow in parts, but eventually the doctor, who keeps promising and not delivering, gets jumped on by the dwarf. Glen Strange's Frankenstein monster is not all that great, just growls and runs from the mad mob. Maybe it's the mob that is the real monster.
Karloff is great as he puts his own command and activity into a bland script, which was clearly written just to see how many monsters Universal could squeeze into a couple of hours.
This film is part of the Legacy of Frankenstein collection which you must see to get not only the full effect of "House" and other Universal horror films in the Frankenstein line, but also film historian interviews and a talk with Sara Karloff, the daughter of The Monster!