Based on Disneyland's theme park ride where a small riverboat takes travelers through a jungle filled with animals and reptiles, Dr. Lily Houghton (Emily Blunt) recruits Frank Wolff (Dwayne Johnson) to guide her downstream on a supernatural quest to uncover an ancient tree that possesses the power to change the future of medicine. The unlikely duo encounters plenty of danger and obstacles along the way that are hidden in the deceptive beauty of the lush rainforest. But secrets that raise the stakes of the mission are unveiled as they get closer to the tree, and Frank and Lily vie for success as mankind hangs in the balance.