River of the Sun — Bill Craig

Sent deep into the Matto Grasso Region of the Amazon jungle, Michael "Hardluck" Hannigan and his friends are searching for the remains of Colonel Percy Fawcett. They are to prove or disprove the existence of the lost city of Z, a fabled Atlantean outpost. Dogged by Nazi spies, Hannigan and company journey deep into the Amazon and discover that not only does Z exist, but that it poses a threat to the entire world at large. Can Hannigan and company stop Z's plans to rule the world? Or will they simply die, vanishing into the depths of the Brazilian jungle?