In these first minutes we've crossed into a timeless world where technological and agrarian artifice mingles with the arcane; where people dress in both contemporary and quaintly antiquated clothing, and where mundane laws and continuity from movie to movie do not apply. Here be monsters, both human and otherwise, walking the shadows, strutting and fretting their hour on the stage while leering at the face of convention. Only in this world can art director Jack Otterson's expressionistic and cavernous rooms, filled with overbearing archways, oddly intersecting but precise angles, large, recklessly sprawling wooden staircases without handrails, and sparse furnishings accentuating the cheerless emptiness of castle Frankenstein, be accepted as commonplace. Even the outrageously large metal knocker that Inspector Krogh pounds against the front door to announce his arrival seems normal given the rest of the peculiar architecture in Frankenstein's fiefdom.
Falling under the black shadows of Frankenstein's legacy, the surrounding countryside is just as cheerless and surreal. Filled with barren, gnarled trees, mist covered tombstones tilting left and right, and hanged — but still kicking — Ygor shuffling around, gleefully playing a dirge on his horn to annoy already agitated villagers, we see the spook show trappings that would move to the forefront of Universal's later movies.
In Philip J. Riley's Son of Frankenstein: Universal Filmscripts Series Classic Horror Films Volume 3, it is mentioned director Rowland V. Lee made sure to use third-billed Lugosi as much as possible after the studio cut the former Dracula star's weekly salary in half, and insisted all his scenes be shot in one week. Not in the original shooting script to begin with, the character of Ygor was hastily crafted by Lee and writer Willis Cooper as production started. Not much of the finished film comes from the script, either, but what evolved is a pastiche of earlier, more introspective, horror elements stitched onto a fresh body more suited to wartime-worried audiences. But it is Ygor who steals the show.
Bela Lugosi, originally signed to play a police inspector in the film, had the role of a lifetime literally improvised on the set — the broken-necked, snaggletoothed Ygor, the monster's demented shepherd. Gone completely was any hint of Dracula; here, for virtually the only time in Hollywood, was Lugosi as the versatile character actor he really was. Unfortunately, Hollywood paid little attention, and would never extend Lugosi such an opportunity again. — David J, Skal in The Monster Show: A Cultural History of Horror
Ygor, who's been using the monster to do his dirty work, insists Wolf Von Frankenstein revive his only friend, made comatose by a lightning bolt strike. Oddly enough, it's a lightning bolt the monster seeks in the later Ghost of Frankenstein to innervate him, but here he's knocked senseless by one. Frankenstein's son can't resist the challenge, and soon the villagers are throwing rocks at the large boxes of equipment heading for the lab — hey, wait a minute, didn't his dad's lab get blown to smithereens in the last film? Oh, right, continuity and Hollywood don't mix. Why not throw in a boiling pit of sulfur that's been around since the Romans, while we're at it, then? And make sure to stick it in the middle of the lab and leave out the safety guard rails. Okay. We're good.