In the 16th century, Don Aguirre leads Spanish conquistadors to South America in search of the Tears of the Moon, a mythical tree whose petals can cure any illness, heal any injury, and lift any curse. After most of his men died in the jungle, the survivors are nursed back to health by a local tribe using the tree petals.
When the village chief refuse to reveal the location of the tree, Aguirre stabs him and his men started attacking the villagers and destroy their village. As punishment, the conquistadors became cursed by the dying chief to never be able to leave sight of the river or the jungle would take them back to it for all eternity.
In 1916 London, Dr. Lily Houghton and her brother, MacGregor, present Lily’s Tears of the Moon research to an association of Royal Society explorers, explaining that the petals could revitalize medicine and aid in the British war effort. The Houghtons request access to an arrowhead recovered by Dr.
Albert Falls that Lily believes is key to locating the tree. When the association denies their request, believing the tree is a myth and a female scientist is unqualified to join their ranks, Lily steals the arrowhead. She narrowly avoids Prince Joachim, a German aristocrat who also wants the arrowhead to find the tree.