Based on Disneyland’s theme park ride, a small riverboat takes a group of travelers through a jungle filled with dangerous animals and reptiles but with a supernatural element. Dr. Lily Houghton enlists the aid of wisecracking skipper Frank Wolff to take her down the Amazon in his dilapidated boat. Together, they search for an ancient tree that holds power to heal – a discovery that will change the future of medicine.
In the 16th century, Don Aguirre led Spanish conquistadors to South America to search for the Tears of the Moon, a mythical tree whose petals cure illness, heal injuries, and lift curses. After many conquistadors die, a local tribe heals the survivors with the tree petals. Unfortunately, the tribal chief refuses to reveal the tree’s location, and Aguirre stabs him and destroys the village. The dying chief curses the conquistadors, making them immortal and unable to leave sight of the Amazon River for all eternity. The jungle recaptures anyone attempting to escape.
In 1916 London, Dr. Lily Houghton’s Tears of the Moon research is presented by her brother, MacGregor, to the Royal Society, claiming that the tree’s petals could revolutionize medicine and aid the British war effort. The Houghtons request access to a recently acquired arrowhead artifact. Lily believes it, along with an old map, is key to locating the tree. Society denies the request, believing the tree is a myth and female scientists are inferior. Lily steals the arrowhead, narrowly evading Prince Joachim, a German royal seeking the tree to help Germany win the war.