It's a black-and-white murder mystery thriller. "It's very 1940s" was my reaction... or rather, more specifically, it's just like British and American cinema from that decade. It doesn't resemble other Japanese films. It's more like RKO or Universal, from the short running time to the oddly anonymous but also quite fun orchestral score. A young woman (Yurie Obata) is the only suspect for a murder. Visiting her home, though, the investigators find a family of slightly creepy oddballs who don't like each other and claim to be cursed by what they call the "Rainbow Man".

People then start dying while calling "rainbow rainbow!"

It's quite a solid murder mystery, based on a novel. The clues are logical and satisfying. I should have picked up on some of them myself. There are two sets of investigators: (a) the no-nonsense police, and (b) two rival journalists who may or may not be heading for a romantic finale with each other. The latter are Mimi Torikai (a friend of the accused) and Ryosuke Akashi (perfectly acceptable as a movie sleuth but not that memorable). The detectives don't matter too much, though. We like them. They do their job, but they're not the important part of the movie.

What matters is that family. An elderly scientist thinks rainbows are more important than anything else. His rich wife is convinced he married her for her money. A painter with a limp does weird, somewhat surrealist paintings that he'll claim symbolise his family. A younger brother has just returned from a five year disappearance, wearing gangster sunglasses and a very un-Japanese beard. Then, of course, there's Yurie, with a secret she daren't even tell Mimi.

For a while, a supernatural explanation seemed possible. The Invisible Man, perhaps, or some crazy invention of the mad scientist. There's that kind of atmosphere. "We're not human! This house is a nest of devils!" A major exposition scene for no reason (except atmosphere) has glowering gloomy lighting and a storm outside. There are also special effects by Eiji Tsuburaya, who five years later became famous for Godzilla. (When a victim sees rainbows, the normally black-and-white film flashes up coloured stripes.)

Overall, it's a decent, workmanlike bit of pulp that would sit nicely alongside The Saint, Charlie Chan, Basil Rathbone's Sherlock Holmes, etc. It's so similar to Western films that its Japanese characters wear their shoes indoors. Mind you, its focus isn't really on the detective investigation. You could imagine it from 1940s Universal, although they might have leaned harder into the horror angle. It's more of a dysfunctional family drama, really, except with killings.