Much of La niña santa takes place in a mysterious thermal-water hotel in northern Argentina during winter. Helena and her teenage daughter Amalia live at the hotel, where Amalia takes part in Catholic discussion groups at a parish. During a medical conference at the hotel, Amalia is sexually approached on the street by a man whom she later discovers is Dr Jano, one of the doctors staying there. Convinced that it is her mission to save him, she keeps the encounter secret. A love triangle and a series of misunderstandings bring the characters’ lives together until everything erupts.