Joan Wilder is a successful romance novelist who leads a rather uneventful life in New York City. Early in the film, she receives a map and a letter containing a message from her sister, who has been kidnapped by a Colombian drug lord named Zolo. The letter tells her that if she wants to see her sister again, she must go to Cartagena and deliver the map to Zolo's henchman.
Joan sets out on her journey, but she gets lost in the jungle and ends up stranded without food or water. Along the way, she meets Jack T. Colton, an American adventurer and fortune seeker who agrees to help her get to Cartagena in exchange for a share of the ransom money. However, as they journey further into the jungle, Joan and Jack discover that the map they possess may lead to a far greater treasure than her sister's release.
Their quest takes them through a series of wild and dangerous adventures, including encounters with crocodiles, mudslides, and Zolo and his army of mercenaries. As they work together to stay alive and complete their mission, feelings between Joan and Jack begin to grow, and the two eventually fall in love.
In the end, Joan and Jack find the treasure and defeat Zolo, with Joan using her newfound courage and bravery to rescue her sister. The film concludes with Joan returning to New York with Jack, who gifted her a new manuscript for her next novel - an adventure inspired by their journey through the jungle.