When Carmen, an 80-year-old widow, suffers a domestic accident, her daughter Lourdes decides to hire an assistant to help her in her daily life. Accustomed to living alone, Carmen rejects all applicants and feels invaded in her own home, which makes her daughter desperate and her life is affected by the constant attention her mother requires. The distressing parade of maids takes its toll on Lourdes' marriage. Mario, her husband, is forced to turn down an important job offer. Lourdes, fed up with the process of interviewing, hiring and firing, argues with her mother, which makes her feel guilty. When it seems that no assistant will ever be able to take care of Carmen, Blanca arrives, a woman of angelic appearance, she is kind, efficient and resolute. But things are not as everyone expected. Blanca hides a secret that will change Carmen's life forever.