The film's premise is partially set in 1931 during the Spanish Civil War, where a group of children are brought to a monastery turned hospital for medical testing. None of the children are capable of feeling physical pain, something that Dr. Holzmann (Derek de Lint) hopes to remedy with his procedures. However at the same time his colleague Dr. Carcedo (Ramon Fontserè) believes that the children would be better off locked up in his asylum in Canfranc. One young patient named Benigno (played at different ages by Ilias and Mot Stothart) stands out in particular, as he proves to be exceptionally intelligent but also easily prone to violent outbursts - something that Carcedo believes is further proof of his beliefs. Holzmann's plans are ultimately never brought to fruition, as the hospital is besieged and taken over by several different military forces.