contains some plot spoiler . i desperately try to like this have first see it age eight and but what seem excite or scary back then and i find pretty lame now . it in the style of raider of the lose ark or romance the stone and but not half a good . set in central america ( not in south america and where it claim belize be ) the story follow the u army set up a low frequency transmitter a a navigational aid to sub . a a precaution this beacon be to be hidden deep underground and to help locate a suitable place be elite mercenary and caveman rupert wolfson . when men operate the transmitter mysteriously disappear and ` wolf and some anthropologist help in the search which take them deep into the mountain . here they encounter unforeseen peril and include a race of temperamental albino . actually film in alabama and tennessee ( cathedral and cumberland cavern respectively ) this suffers from dreadful act and screenplay and plus lack of imagination a the amystery unfolds ( not to mention numerous continuity and editing error ) an atmosphere of intrigue and ambiguous wonder be create to ( almost ) good effect at the beginning and with the opening monologue discussing unexplored wonder of the earth accompany by eerie music . this ambience be lose after some badly direct action and almost ruin the following helicopter distort lens sequence and meander u through the unwelcoming landscape like a drunkard . ` 2001 style wonder be pair with suspense a we enter the cavern and combine some good cave location with matte artwork and photography . but the camera seem more interested in what our character be do . before long the low budget be apparent and aside from some interesting monster and be treat to silly set and costume . characterisation be base on racial stereotype and the general level of stupidity of that person . take our main character represent he be suave englishman wolfson and act a a consultant for the army while an expertfighter and all around good guy . no personality flaws and only bad dresssense . two ugly english ( natch ) play scientist who be specifically there to die . the female lead ( obligatory love interest ) be talkie ( but not outspoken ) leslie . work with the anthropologist she help extract long dead remains but will scream when face with a fresh one . not too bright . the main american contingent play embarrassingly inept and unprofessional soldier obsess with work the transmitter a if their life depend on it . wolf friend george only importance to the plot be to tell wolf about the mission . he be a lieutenant and an idiot . there be also several local latin american assist the u and one be accident prone santos who act a a plot device to attract the monster . acting be at best poor and veteran robert powell doesn not even try to get to grip with his ( admittedly awful ) script . apparently the main script be be rewritten every day during the shoot and it show . there be some good ` predator style effect a the human be view a a pink glow through the lemurians eye and but their rock shatter scream be unconvincing . i do like the idea that the lemurians be sensitive to ultra sonic wave though . the plot badly lose it way . the buildup be painfully slow and when the amystery be finally resolve and it a real anti climax ( not give anything away and let say not exactly a close encounter moment ) the idea of discover creature deep inside a tropical mountain landscape appeal to me and but ` secret of the phantom cavern be a letdown . underground albino .