Plot
The story begins during a boxing match of Esperanza Muñoz—nicknamed "Monita"—who has sustained a hand injury. Her manager, Enrique "Quique" Ferreti, is pressuring her to continue fighting, despite her pain. This injury complicates her economic situation, as her boxing provides the only income for her adoptive family, namely Quique and his mother, Maria de las Nieves. Nieves loves Esperanza like her own daughter, and pressures her to marry Quique. Her neighbor Kimberly suggests that Esperanza apply for a job in the Quesada Group, where she works as a janitress. The secretary Mercedes rejects Esperanza due to her violent manners and her dressing style. Martín Quesada, the president of the company, sees Esperanza crying in the street and hires her as his personal assistant.
Martín also meets three orphan siblings, José, Laura, and Coqui, who resisted being adopted by different families. He takes them to his home, and starts the legal proceedings to adopt them. Martín begins to like Esperanza, but his girlfriend Constanza, a cold, manipulative, and malicious woman, is wary of her. Esperanza does not tell Martín about her relations with Quique, instead pretending to be his sister. She also does not tell Martín that she is a boxer. Quique and Constanza begin their own relationship, unknown by most other characters. Martín breaks off his relationship with Esperanza when he sees her goodbye kiss with Quique, as he realizes that she was lying to him.
After the breakup with Esperanza, Martín resumes his romance with Constanza and eventually proposes marriage to her, in order to improve his chances of winning custody of the three siblings. The judge, who thought that Esperanza was a bad influence on the children, gives the adoption to Constanza instead of Martín, forcing him to marry her. Their marriage proves difficult; Constanza is demanding and possessive, and despises the adopted siblings, who hate her as well. Martín finally breaks with Constanza when she pretends to be blind to keep him with her. The children's custody battle delays the divorce, as Martín wants to keep them.
Due to the efforts of Martín's cousin Miguel, the unscrupulous lawyer "Falucho", and Constanza, Martin gradually loses his fortune, his business, and his house. He moves to the Conventillo and works as a taxi driver. Eventually, he recovers everything. A new character, Bárbara, temporarily joins the love triangle of Martín, Esperanza, and Constanza. Constanza gets pregnant by Quique and tries to pass off her son as Martín's, but fails. Martín finally marries Esperanza and has a family with her and the adopted children. Constanza moves in with Quique.
