Where the River Runs Black (1986)

Father O'Reilly, an older priest, tells the story of Father Mahoney, Eagle Woman, and their son Lazaro. It's magic realism in the Amazon. Mahoney is a radical priest who ventures upstream where the river runs black. He encounters the beautiful and enchanting Eagle Woman, who can change from a dolphin to a woman. A few years later, their child Lazaro witnesses inter-loping gold prospectors commit a brutal and traumatizing murder. He goes to the city in Father O'Reilly's care, and there he sees the murderer, who's a politician. Lazaro seeks revenge, which puts him in further danger. He runs back into the jungle, where the dolphins may be his best hope for help.