Nathan's grandmother & her husband Walter became stranded in the remote Amazon jungle. Separated from her husband, whom she believed was still alive (the rest of the surviving crew were actually killed and eaten by the Yaneemango), she was then taken in by the Yaneemango.
She eventually fell in lust with Otoe, claiming in her diary they were powerful together. Otoe later feeds his new wife a soup made from Walter's remains. Nathan's grandmother found out when she discovered her late husband's watch in the soup.