1972. In an industrial city in Catalonia, two textile workers with totally ordinary lives and occupations are found lying decapitated across the train lines. Beside their bodies is a farewell note reading: ''THE ALIENS ARE CALLING US. WE BELONG TO THE INFINITE.'' It is the final years of Franco's regime and Spain is powerless to escape the boom years of the UFO, a fad that's all the rage around the globe. But here, any kind of free association is open to investigation as a potential hub of subversive activity. Juan and José, whose passion for flying saucers is no more than an attempt to escape from the reality of a dull and desolate political and cultural milieu, are sad victims of this tense, schizophrenic climate.