When Refugio and her three sons—Patricio, Edmundo, and Ignacio—are forced out of their home, a twist of fate brings them to Mexico City, where they begin a new life. Eighteen years later, they are settled in a small apartment in a working-class neighborhood. Refugio holds a modest job; although she suffers from serious vision problems, she neglects her own health to attend to her sons' needs. Patricio is studying law and dreams of a comfortable, prosperous future; his mother admires him for his charitable nature. Meanwhile, Edmundo begins courting Lucero—unintentionally hurting Ignacio, who secretly loved her—while Refugio tries in vain to make Patricio understand that he will never be happy with Olga.
