"The Secret of the Lost City" is an adventure film that follows the journey of a reclusive author named Loretta Sage and her cover model, Alan. They embark on a quest to find a legendary city filled with treasure, which is believed to be hidden in the jungle. Their adventure takes unexpected turns as they face various challenges and dangers along the way. As they navigate through the wilderness, Loretta and Alan encounter a group of mercenaries led by Abigail, who are also searching for the lost city. The film combines elements of comedy and action, showcasing the growth of Loretta and Alan's relationship as they work together to uncover the secrets of the lost city.