When Andrés Ruzo was a young boy in Peru, his grandfather told him a story with an odd detail: There is a river, deep in the Amazon, which boils as if a fire burns below it. Twelve years later, after training as a geoscientist, Ruzo set out on a journey deep into the jungle of South America in search of this boiling river. At a time when everything seems mapped, measured and understood, join Ruzo as he explores a river that forces us to question the line between known and unknown ... and reminds us that there are great wonders yet to be discovered.