THE UNKNOWN TERROR (1957)

Jim has gone "south of the American continent" in search of the legendary Cave of the Dead, but has vanished without a trace. His sister Gina (Mala Powers) and her husband Dan (John Howard) undertake an expedition to find him, joined by Pete (Paul Richards), an old flame of Gina's who saved Dan's life years ago in a spelunking accident but who now has a permanent limp. In a Central American village, they get some help from Raoul, an interpreter. They hear a local folk singer sing a song with veiled references to the Cave of Death, with the cave as a kind of purgatory for the newly dead, but when they ask Raoul to interpret it, he refuses and runs off. An American doctor named Ramsey (Gerald Milton), who spends most of his time experimenting with molds grown in jars of fruit, tells them that the cave does not exist, but also mentions the human sacrifices that occur occasionally in the village, and says he saves the people from death and puts them in "a safe place." Ramsey's wife, a local woman named Concha, flirts a bit with Pete and soon takes him off to the jungle to hear the rumored voices of the people in purgatory. What develops is that Ramsey has been putting the villagers he saves in the Cave of the Dead, which is right below his house, and experimenting on them with the fungi he grows, turning them into fungus monsters who occasionally escape and wreak havoc aboveground. These are the purgatory voices that Concha hears. Later, Gina is menaced by a creepy deformed mutant, one of Ramsey’s subjects, at her bedroom window. The climax involves lots of cave exploring, lots of bubbly fungus dripping down the walls of the cave, and a possible threat to the entire planet from the fungus, which has gotten out of Ramsey's control.

This little-known second feature is completely average for its genre, horror with SF and adventure elements. I like the ideas that drive the plot—the experiments, the sacrifices, the enigmatic folk song, the vague outline of a romantic triangle—but despite the sheer number of plot points, things still bog down here and there, especially as we near the climax. Old pro Howard (Bulldog Drummond, The Philadelphia Story) is good, giving no sign of thinking he's slumming. Powers is in her element as the damsel in distress. Paul Richards is a bit too low-key as the noble sufferer (whose handicap sort of comes and goes depending on the scene). Gerald Milton doesn't bring much to the mad doctor part. The movie looks way better than it has a right to; the Blu-ray print of the black and white widescreen film is clean and vivid, and the sets are good, though the fungus effect, mostly tons of soap bubbles, leaves something to be desired. Its production values put it ahead of the typical Roger Corman horror flick of the day, but it lacks the rough charm of those movies. The folk singer is Sir Lancelot, the calypso singer who features prominently in Val Lewton's I WALKED WITH A ZOMBIE. Pictured are some of the fungus monsters in the cave. [Blu-ray]