María (Hilda Aguirre) is a young orphan woman who lives with her wealthy aunt (Margot Cottens). María enjoys singing in a nightclub with her friends, who have a rock band called "Los Yakis Voladores". Her friend Ernesto (Enrique Guzmán) is in love with her but she doesn't think she feels the same. In fact, her many existential questions and a strange emptiness she feels in her life suddenly compel her to enter a convent as a novice. This breaks Ernesto's heart and she isn't the best fit for a convent with her happy, open, rebellious nature. The headmistress tries to lead her in the right direction by chastising her. The convent is also a children's hospital and Maria meets a doctor (Manuel Gil) with whom she has a personality clash although they develop a mutual liking and respect. Meanwhile, the convent is going through financial difficulties and the nuns must deny themselves food so all the children will have enough. They also need money to get a blind child an operation and to prevent the closure of the convent itself. Maria goes to her aunt to ask for a "voluntary" donation, but her aunt furiously sends her away. After asking permission from the Mother Superior and the bishop, Maria decides to compete in the Sanremo Music Festival, thinking that the first-prize purse will be enough to save the convent forever. But Ernesto will be among her competitors. Meanwhile, is she really meant to be a nun, or does she have a future with that doctor?