"The scene is San Juan el Pirata -- It is 20 years since Juanita died; and The Three-Cornered Halo concerns itself with the not wholly altruistic efforts of her people to arrange for her canonisation. A halo for Juanita would bring great benefits to everyone on the island-from the Hereditary Grand Duke himself, right down to the Chief of Police and his happy band of smugglers, not to mention his innumerable relatives with their large stocks of horrid dried fungi in little paper bags. Yet the Grand Duke refuses to recommend the Pearl of San Juan for beatification. There is murmuring against him and, at last, an assassination plot; and into this are drawn, to their very reasonable dismay, a number of visiting tourists..."