James Morrow 
Wine of Violence 

Marooned on the planet Quetzalia after their ship clashed with the irresistable force of gravity, Day One In Paradise is not quite the blissful Utopia fact-finding Nearthlings Francis Lostwax and Burne Newman were expecting.Tropical fronds turn out to be brain-eating Neurovores who decimate the rest of the scientists’ crew, and a sweeping, majestic river becomes a bubbling cauldron of caustic 'noctus’ or liquified hate.Abandoning their craft, the two scientists flee to the Quetzalians, a peace-loving race guided by the precepts of the Ancient Mexicans. Together they vow to rid the planet of the evil Neurovores.But the technology-free Quetzalians demand that the Nearthlings destroy their machines and with them their lifeline back to the planet New Earth…