As if the unseen presence of these evil spirits were not bad enough, the Quechuan-speaking Indians who inhabit the remote Andean communities, the descendants of the Incas who once held majestic but bloody sway here, are still in the grip of Sendero Luminoso (the "Shining Path"), the outlawed Maoist guerrilla organisation which, until his capture in 1993, was presided over by the sinister professor, Abimael Guzmn. His terrorist movement has been responsible for the worst violence and bloodshed in modern Peruvian history and, for a time, it succeeded in making the country virtually ungovernable.
Observing the bizarre antics that take place in the sierra village of Naccos are two Civil Guards, Lituma and Carreno - a sort of South American Rosencrantz and Guildenstern - both decent men of humour and goodwill, whose task it is to investigate a series of unexplained disappearances.
Lituma is a pragmatist, a man from Piura on the coastal plain, who is mystified by the strangeness of life in the mountains, while his adjutant Carreno can think of little else in their lonely outpost apart from his beloved Mercedes, the first woman he has ever slept with, whom he rescued from the hands of a rapist, lost and subsequently regains. The two men's brilliantly sustained comic dialogue is the thread that holds the various and complex strands of the novel together, while the drawn-out progress of Carreno's love affair serves as a fugue motif to the principal action.
All echelons of Peruvian society are represented in Death in the Andes. Particularly memorable is the philanthropic and fearless Senora d'Harcourt from Lima, whose main concern is the preservation of the environment. "She's an idealist like you," her friend, an engineer involved with a foreign-aided reforestation programme, explains to their terrorist captors. "She wants a better life for the campesinos." But it is to no avail: "This is war and you are a lackey of our class enemy... a tool of imperialism and the bourgeois state," replies a man with a cold stare, presumably meant to represent the fearful Guzmn.
Other victims of Sendero Luminoso include two eager young French tourists, typical of the sweetly innocent backpackers who troop up the heights of Machu Picchu in their hordes, who are bludgeoned to death for no reason other than that they are gringos. "It isn't race that separates us, it's an entire culture," observes la petite Michele to her boyfriend before they are ruthlessly murdered.
But whether Sendero is also responsible for the three men who have disappeared is a question never resolved. The cruelty inflicted on one of them, the trusting, half-wit, mute shepherd Pedrito Tinoco, who is forced to witness the slaughter of the vicuna he tends so lovingly, and whose silence is assumed by the police to indicate that he himself is a terrorist, could equally well be something to do with the curious local bar-owner and his witch-like wife, Dona Adriana, who are said to lead troupes of wild revellers over the valleys, performing strange Dionysian rituals.
"In the old days," Adriana reflects, "people had the courage to face great troubles by making sacrifices. That's how they maintained the balance. Life and death like a scale with two equal weights, like two rams of equal strength that lock horns and neither one can advance or retreat."
Vargas Llosa's vision of modern Peru as seen from the perspective of an otherwise insignificant mountain community is built up kaleidoscopically and with technical mastery through a variety of viewpoints, voices and sudden shifts of narration.
No single theme emerges: Vargos Llosa's novels are never neatly resolved and neither is anything else in a country like Peru, with its authoritarian traditions and class divisions, ever a prey to the machinations of political ideologies and the destruction of its ecology for commercial greed.
"I wonder," a character in Death in the Andes asks himself, "if what is going on in Peru isn't a resurrection of all that buried violence." The blood that the Incas and their predecessors once sacrificed is still being shed in the 1990s, Vargas Llosa seems to suggest.
The world they inhabited before the ravages of the Hispanic conquest has still not been entirely tamed, and the spirits their ancient civilisation conjured up are unlikely to be placated.