La Madrastra is a Mexican telenovela that aired on El Canal de las Estrellas in 2005. The program's main character is María Fernández Acuña, a woman who returns to Mexico after spending 20 years in prison for a murder she didn't commit only to find that her children believe that she is dead and that the picture of an unknown woman hanging above their fireplace is their mother. The telenovela follows María's attempts to regain her children's love without telling them who she really is, her complicated relationship with her ex-husband, Esteban, and her quest to find out which of her former friends really killed Patricia. Including María, the main cast consists of approximately twenty-five characters, as well as other recurring or minor characters.

Main characters

María María Fernández Acuña (Victoria Ruffo), the series protagonist, is wrongly sentenced to life in prison after her friend, Patricia, is murdered in Aruba. After twenty years, María is released for good behavior and returns to Mexico City to confront her husband and friends who abandoned her, and to reunite with her two children, Héctor and Estrella. Despite originally doubting her innocence, María rekindles her relationship with Esteban, and they remarry so that she can be closer to her children, whom she fears to tell that she is their mother until she has cleared her name. However, María's children resent her and consider her to be their wicked stepmother who is trying to usurp their mother's rightful place. After María's name is cleared, she and Esteban finally tell their children the truth, and María is reunited with her children as their mother at long last.

The Suspects Esteban San Román (César Évora), an important and wealthy businessman, divorced María after she was convicted of Patricia's murder, told their young children that their mother had died in an accident, and erected a portrait of another woman above their mantle. He also adopts a third child, Ángel, who is really the illegitimate son of his aunt Carmela, to avoid scandal. Despite the fact that he is engaged to Ana Rosa, Esteban quickly finds himself attracted to María once more and remarries her so that she can be closer to their children. After the discovery of a letter that incriminates him in Patricia's murder, an Aruban court finds him guilty of the crime and sentences him to death; he is saved literally minutes before his execution, and when he returns to Mexico he informs his children that María is their real mother. Alba San Román (Jacqueline Andere), one of Esteban's aunts, and her sister Carmela raised Esteban following his parents' deaths. About twenty years ago, Alba had an affair with Demetrio, who was also sleeping with Carmela; subsequently, both women became pregnant, and when Alba's child was stillborn, she switched infants with her sister and then allowed Esteban to raise the child, Ángel, to avoid scandal. Despite their blood relation, Alba harbors a forbidden love for Esteban and thus loathes all of the women who are in love with him, including María and Patricia. After being rejected by Esteban, Alba falsely accuses Esteban of murdering Patricia and then commits suicide by jumping from the roof of the San Román mansion. In the alternate ending, Alba frees Esteban from prison after she decides that she has to turn a new leaf, and after she is forgiven by all that she has harmed, she decides to leave Mexico for some time. Bruno Mendizábal (René Casados), an ambitious man with a penchant for eyeliner, is one of Esteban's business associates. He is husband of Fabiola, who married him out of convenience after Esteban rejected her. They had one son who was born with severe physical deformities as a result of their abuse of alcohol, tobacco, and drugs; they subsequently abandoned him in a Canadian institution, only paying for his care. Patricia eventually came to learn this secret, thus providing him with motive for her murder. However, it is eventually revealed that Bruno was having a passionate affair with Patricia at the time of her death, and that she was pregnant with his child when she died. Two decades later, Bruno and Fabiola maintain a conspicuous, glamorous lifestyle. However, following their son's death, Bruno and Fabiola's marriage begins to deteriorate rapidly. In the original airing, the couple realize that they are in love and agree to become better people, with Bruno removing his trademark make-up and abandoning his obsession with his image. In the 2007 ending, Fabiola stabs Bruno to death in a fit of insanity after he discovers that she murdered Patricia. Fabiola de Mendizábal (Sabine Moussier), a haughty and arrogant woman, is married to Bruno, whom she wed after her fiancé Esteban left her and married María. Twenty years ago, Fabiola gave birth to a son who suffered from extreme birth defects as a result of her and Bruno's wild lifestyle of alcohol, tobacco, and drug use. Horrified, the couple placed him in an institution in Canada; they never visited their child and swore to never speak of him again. Two decades later, Fabiola remains in love with Esteban and schemes to win him back. However, after her and Bruno's son dies, she becomes wracked with guilt. In the original 2005 airing, Fabiola leaves Bruno, only for the two to realize that they really do love one another; they reunite and pledge to become better people, leaving the glamorous personalities that they had created behind them. However, in the alternate airing, Fabiola is revealed to be Patricia's murderer, and she stabs Bruno to death in a fit of insanity after he learns of her guilt. After attacking María, Fabiola is placed in a mental institution. Daniela ex de Rivero (Cecilia Gabriela), a fragile woman with a propensity to tears, is married to Demetrio, the corporate lawyer at the Empresas San Román. Demetrio was previously married to Daniela's sister, Sofía, who was engulfed by madness after becoming addicted to pills. Daniela allowed her sister to overdose; after Sofía's death, she married her former brother-in-law and took in Sofía's daughter, Ana Rosa. Despite her emotional sensitivity, Daniela is an ambitious woman and encourages Ana Rosa's relationship with Esteban, despite the fact that she herself secretly harbors romantic feelings for Esteban. Daniela is devastated to learn that Demetrio fathered a child, Ángel, with another woman and tries to save their marriage, but ultimately leaves Demetrio when she learns that he has been sexually abusing Ana Rosa since she was a young girl Demetrio Rivero (Guillermo García Cantú) is a lawyer at the Empresas San Román, and is frequently regarded by many of the series' characters as a failure of a man. Much of Demetrio's assets are the result of his first marriage to his current wife Daniela's sister, Sofía; Demetrio's investments and business deals frequently go awry, and as a result he embezzled a significant amount of money from the Empresas San Román about twenty years ago. In the original ending, it is revealed that Patricia discovered several of Demetrio's secrets: his embezzlement; his affairs with Alba and Carmela, the latter of which resulted in the birth of Ángel; and the fact that he is a crossdresser. As a result, Demetrio murdered Patricia to keep his secrets safe. After Demetrio's crimes are revealed to the audience, he quickly spirals into insanity and is arrested after attempting to murder Bruno, Fabiola, María, and Esteban. In the 2007 ending, Demetrio reunites with Ángel and Carmela as a family in the finale. Carmela San Román (Margarita Isabel), one of Estaban's aunts, and her sister Alba raised their nephew following his parents' deaths. Carmela has always been weaker than Alba and is frequently manipulated into doing her bidding. Twenty years ago, Carmela had an affair with Demetrio, unaware that he was also sleeping with Alba; subsequently, both women became pregnant, and Carmela believed that her child died, while Esteban raised Alba's son, Ángel. However, following a relapse of leukemia, Carmela learns that Alba switched infants, and that Ángel is really her son. Carmela happily reunites with her son and renounces her sister. Servando Maldonado (Lorenzo de Rodas) is the miserly business associate of Esteban who falsely provided testimony against María in Patricia's murder trial twenty years ago because he was in love with María and hated her for not reciprocating his emotions. After learning that he is dying, Servando hides numerous letters confessing the true murderer's identity and arranges to divide his considerable fortune between his mute maid, Venturina, and the stepbrother he had abused as a child, Rufino " El Pulpo" Sánchez. Servando is smothered to death by an off-screen Demetrio, who fears that he will reveal his identity, but the other characters assume that he died of natural causes. After his death, one of Servando's letters is discovered and implicates Esteban in Patricia's murder as a means of hurting María yet again; it is turned over to the police, and as a result Esteban is extradited to Aruba, where he is tried for Patricia's murder. In the alternate ending, Servando dies of natural causes.

The youth Leonel Ibáñez (Eduardo Capetillo) is the son of Patricia and Arturo who was orphaned at a young age after his mother was murdered and his father subsequently died of a broken heart. Esteban took the young boy under his wing, telling him that his mother had died in an accident. Leonel falls in love with María when she returns to Mexico, unaware that she has spent the last twenty years in prison for his mother's murder. After María remarries Esteban, Leonel eventually reciprocates his secretary Lupita's feelings, and they are married in the finale. Ana Rosa Márquez (Martha Julia) is the twenty-something fiancée of Esteban who was raised by her aunt Daniela following the death of her mother, Sofía; both Sofía and Daniela have been married to Demetrio, who has sexually abused Ana Rosa since she was a young girl due to her resemblance to her deceased mother (also portrayed by Julia). Ana Rosa and Daniela scheme together to secure Ana Rosa's marriage to the wealthy Esteban, despite the fact that Ana Rosa continues a relationship with the social-climbing Carlos. Ana Rosa shows signs of being afflicted by the same madness that claimed her mother and shoots Esteban in an attempt to murder María, but after a stint in a psychiatric clinic Ana Rosa turns over a new leaf and attempts to become a better person. She discovers a videocassette revealing Patricia's murderer and attempts to turn it over to the Aruban authorities, but she is lured to an abandoned warehouse and murdered by Demetrio before she can expose him. In the alternate ending, Ana Rosa has a happy ending and is in a committed relationship with Dr. Ruiz. Héctor San Román (Mauricio Aspe) is the son of María and Esteban. An executive at his father's company, Héctor becomes determined to prove his independence from his father when Esteban becomes engaged to Ana Rosa, and again when Esteban marries María, because he loathes the idea of a stepmother. Héctor briefly warms to María when she pays off his debt from a business transaction gone wrong, but he eventually turns against her once more after Alba accuses María of assault. Héctor marries Vivian, María's former cellmate, when she becomes pregnant, but remains concerned that she is having an affair with Greco and thus begins an affair with Angélica during his wedding reception and begins drinking heavily. Vivian leaves Héctor after discovering his infidelity, but Héctor realizes his errors and convinces Vivian to forgive him before she leaves the country.