Robert Lindsay (Alfred Grant) has just got married to his fiancée Eleanor (Daisy Bufford) today, and as they leave the church to go on honeymoon he sees his lawyer, Bradshaw (Earle Morris) has arrived to greet the happy couple. Eleanor jokes they won't be needing his services soon as he specialises in divorce cases, but there's someone else who does call on him, one of the guests: Dr Helen Jackson (Laura Bowman), a crotchety old dame who demands Bradshaw draw up her will. She has an idea of who to leave her fortune to...
And it's not the bloke she keeps in the cellar in this, a film that did not as the title suggested have anything to do with Ingagi, which was a lurid pseudo-documentary, sort of an early mondo movie, featuring African subjects and a lot of toplessness. No such scandal here, however, as this was a horror movie, not that you'd know it for most of the first half which took up a lot of setting up of the plot; basically, the Lindsays inherit Dr Jackson's manor house, but did not count on the presence of a certain somebody she brought back with her from Africa where she conducted most of her studies.
This throws up more questions than answers, one being if Dr Jackson was the pioneer she claimed to be then why had she imprisoned a perfectly innocent man in a hidden basement room? She may be a rare female mad scientist, but really. Except by the time we meet him he's gone nuts and is let out periodically to strangle anyone who is unlucky enough to visit, and then possibly eat them (that bit is none too clear, but we don't see what happens to the bodies too blatantly). This includes his mistress, who doubles the cellar prison (which has bars on a cell in it) with her laboratory, where she treats us to a scene where she makes an incredible breakthrough but neglects to tell us what it is.
Then again, we'd never know anyway because her pet brute downs the potion and goes on a minor rampage, offing the good doctor in the process. What should be pointed out was this was a desperately low budget affair, but there was a solid reason for that, which was it was an example of the early so-called race films of America in the first half of the twentieth century, movies made expressly for African American audiences without a thought to anyone else seeing them. Most of these were melodramas, thrillers and comedies (Mantan Moreland made quite a few when he wasn't the comic relief among predominantly white casts), but Son of Ingagi had the distinction of being the first all-black horror movie.
Or so went the proud boast on the advertising, but watching this you could well understand why there were not exactly a plethora of such productions when this one came across so impoverished, both in terms of the money behind it and in terms of its thrill count. As if lacking the courage of their convictions, more humorous scenes appeared later on, perhaps suspecting nobody was going to take this wholly seriously, though they were notable too for featuring the writer of this as the Inspector, Detective Nelson as he was Spencer Williams, later to be famous as Andy in groundbreaking (or more likely notorious) sitcom Amos 'n' Andy in the fifties. Here he lightens proceedings a degree, as does an early musical interlude from The Four Toppers (about the only music on the soundtrack, truth be told), but the fact remains there was that old standby, wandering about in a horror movie to pad this out to barely an hour. Historically interesting, but hard to sit through if you're not intrigued.