Although it was made relatively late in the giallo cycle, this mostly Spanish production is kind of an old-fashioned throwback to the late 60's giallos starring Carrol Baker, especially "So Sweet, So Perverse" which co-starred the female lead of this one, Erica Blanc. Like several early Italian gialli this is kind of a variation on the French classic "Diabolique" with a wealthy women, her industrialist husband, and her lover all crossing and double crossing each other. It has many twists in it (some not entirely believable) but it is nevertheless pretty staid and sober compared some of the delirious over-the-top giallo of that era like "Deleria Caldo", "Case of the Bloody Irises" or "Torso".
It's also pretty tame. It takes awhile for a "real" murder to occur, and the anticipated image of a dead body being thrown in a cellar and devoured by rats is not really ever delivered on (whereas it happens in the pre-credit sequence in "Seven Deaths in a Cat's Eye" made the same year). The ever-gorgeous Blanc has her usual gratuitous nude scenes (which itself might be worth the price of admission for some), but the sex and nudity is nowhere near as graphic or perverse as in most contemporary gialli. I suspect this movie probably even played uncut in Spain during the late Franco era. Which doesn't necessarily make it bad, depending on what you're looking for
