Exotic adventure with an unlikely impetus: 16-year-old Fernando, a Spanish duke no less, is about to go home on vacation from his English school when he gets a call from his Scottish mother's sister asking him to go via Andalusia (really well out of his way) to check up on a villa she owns there but hasn't visited in years. Aunt Jane's ""second sight"" tells her that something peculiar is wrong there--and indeed, Nando finds the place a ruin, and occupied sporadically by the ""Dark Ones"" from next door. This last bit of information, and much else, is supplied by Angelito, a homeless gypsy boy who says the Dark Ones killed his family. Nando discovers that the Dark Ones are an international ring of Nazis, and he eventually learns that they plan to kill the Spanish king. Fernando's friend Aha-Maria shows up to help him, and later, much to her distress, her older brother turns up among the Dark Ones: ""But not a Nazi! You, my very own brother. All that racism. You know our best friends are. . . ."" Of course he's not a Nazi, but a spy who gives up his own life in the end to save the king's. Through more than half of the novel very little happens except for ominous glimpses and the children scuttling about to discover more. Then Nando is captured and beaten-more than once; the children's spying tactics become more elaborate and less plausible; the Nazis kick and rant and kill in a melodramatic and stereotypical, not to say senseless fashion; and the action escalates, to the possible satisfaction of the audience for simplistic political thrillers. Skeptical readers or those looking for more rounded human drama will have dropped away.