Ina Montecillo mourns her fourth husband, Eddie at his grave. She and her best friend Rowena then work as a stunt doubles for a film directed by her former employer, Bruno. Four of her children are Overseas Filipinos: her eldest, Juan, migrates to New Zealand with his girlfriend, Jenny. Tudis settles in Canada, where she meets her future husband, a house painter.^[a] Portia/Por breaks up with Jeffrey and moves to India, where she joins GMA (Global Missionaries of Asia).^[b] Sixto migrates to the United Kingdom to work as a nurse.

Of her eight remaining children, Tri, is a law student by day and a call centre supervisor at night. Pip, her gay son still pursues his dream of entering show business; he queues for what he thinks are auditions for PBB, but turns out to be a rice distribution program called Pila ng Bigasang Bayan. Seven, is the one in charge of her younger siblings and household chores. Cate has a dignity to stop everything. Shammy is doing something bad instead of studying, but he can be a businessman. Her deaf-mute son Ten-ten is very quiet while her twin daughters Connie and Sweet are quite naughty. Ina has a restaurant which is bankrupted by Rowena's gluttony.

On the night of her 46th birthday, she prepares a surprise for her children, but none of them remember. She decides to study in university as a working student, taking on a series of odd jobs. Her first stint is as a waitress, but gets fired after removing her uniform in front of patrons due to the heat. She next decides to work in an ice plant, but resigns after Rowena visits her. After that, she continues her studies.

Rowena and Ina go to Malacañang to seek employment. They refuse the positions of governess to the presidential children (thinking it means governor) and chambermaid (thinking it means a selector of chandeliers), they get jobs as maids. They catch a glimpse of President Hillary Dafalong, and scramble to greet her but are stopped by the Presidential Security Group. They try and fail to speak with her several times until Ina eavesdropps on Vice-President Bill Bilyones discussing a plot to assassinate Dafalong. At a public function, Ina and Rowena try to inform the President of the plan but fail because of the crowd's absent-mindedness, and Dafalong is killed. As a result, Ina blows the whistle on Bilyones, who immediately calls for a snap election in which he loses to Ina by a landslide.

Settling into her new role as President, Ina makes initial missteps such as implementing extended night classes for children before improving things through measures such as wholesale arrests of traffic violators, utilizing vacant land for rice production and securing the nation's oil supply by teaching Arab leaders a rain dance. However, Ina's relations with her family become strained. Tri gets into bad company and gets involved in a series of anomalous dealings. Pip stars in indecent films, while Ina unwittingly puts her signature on what she thinks is a school assignment of Shammy, but is actually a contract to set up a gambling den near his school. Her twins, Sweet and Connie, are then kidnapped by terrorists after the girls thought they could ease things by running away. They eventually retrieve the girls and subdue the terrorists, and Ina then decides to resign after realising the value of her family. Ina hands over the reins of power to her vice president, Ren Constantino.

On her 47th birthday, Ina wakes up and thinks that her family forgot again. They fete her with a surprise party to also compensate for forgetting her 46th birthday. In the end credits, President Constantino roams around Malacañang, looking at the official portraits of past presidents. The last portrait shows Ina as President, surrounded by her family.

• Ina Montecillo (Ai-Ai delas Alas): Ina is the mother of Juan, Tudis, Tri, Por, Pip, Six, Seven, Cate, Shammy, Ten-ten, Connie, and Sweet. She is Rowena's best friend. She loves her children very much, even working several jobs to support them including being a maid in the Palace. She accedes as the sixteenth President of the Philippines after uncovering Vice-President Billiones' role in the murder of President Dafalong and defeating him in the ensuing snap election. As she faces several problems with the Philippine economy, she her family's relationships also begin to erode. In the end, she resigns the presidency, and returns to caring for her family.
• Rowena (Eugene Domingo): Rowena is Ina's best friend. She is very supportive of her, and will do anything to make Ina happy. She was also appointed by Ina as Presidential Spokesperson.
• Dimitri "Tri" Montecillo (Carlo Aquino): Tri is Ina's third child. He is a university student reading law. Angry that his mother refuses to let him assist her in policy and decree implementation, he joins the opposition wing of the government. In the end, Ina forgives him as he severs his ties with the opposition.
• Tirso "Pip" Montecillo (Alwyn Uytingco): Pip is Ina's fifth child. Openly homosexual, Pip is in love with a fellow film actor, with whom he is videotaped flirting with in a cinema; the video is later leaked and causes a scandal. Later on, he discovers that a frustrated Tri had joined the opposition against their mother's government. In the end, Ina forgives him for the video scandal.
• Severina "Seven" Montecillo (Shaina Magdayao): Seven is Ina's seventh child. An intelligent girl, she is viewed as "the responsible child", replacing her older sister Tudis' role in the family and Por's role as Jeffrey's girlfriend. When her mother discovers their relationship, she initially separates them, only allowing them to reunite at the end of the film.
• Catherine "Cate" Montecillo (Serena Dalrymple): Cate is Ina's eight child. She is now girly and obedient, unlike her tomboyish, rough role in the original film. She also tends to have many habits that need changing, but, according to Ina, there are too many.
• Samuel "Shammy" Montecillo (Jiro Manio): Shammy is Ina's ninth child. He is very friendly, but very boastful of his mother's prestige and their life in the Palace. He accidentally sets up an illegal gambling business in his school (College Tele-Karera Enterprise or CTE, a parody of the real-life ZTE-NBN scandal that rocked President Gloria Macapagal Arroyo's government in 2007) after his friends tell him to let him sign it for his mother. In the end Ina forgives him, and he dissolves the business after his expulsion from school.
• Martin "Ten-Ten" Montecillo (Yuuki Kadooka): Ten-Ten is Ina's tenth child. He was born deaf-mute, but is very proficient in sign language. It was he who encouraged his mother to become president, and provided her moral support throughout the story.
• Connie & Sweet Montecillo (Bianca & Janella Calma): Connie & Sweet are Ina's eleventh and twelfth children. They are twins, and are normally naughty, but very kind to Ina. When they realised their mother laden with problems, they decided to run away and are kidnapped by terrorists, who demand that the Presidential family pay a ransom in exchange for their release. In the end, they were saved by Ina, who delivered a nationwide television broadcast to appeal to the kidnappers' mothers.
• President Hillary Dafalong (Gloria Díaz): The fifteenth President of the Philippines, she is very kind and helpful, especially to Ina. She remains distrustful of Vice-President Billiones, who engineers her assassination while she was delivering a public address.
• Vice-President Bill Billiones (DJ Durano): Bill is the fifteenth Vice-President and acting President of the Philippines, and a member of the opposition. He is the mastermind behind President Dafalong's death, and is later arrested for murder.
• Jeffrey (John Prats): Jeffrey was Por's boyfriend. After breaking up with her, he begins to court her younger sister, Seven. As Ina continues to break them up, Seven becomes more interested with their relationship. In the end, they end up dating.
• Ren Constantino (Cherry Pie Picache): Ren is Ina's strict yet kindly college teacher who later helps Ina's presidential campaign. Later on, Ina selects appoints her as the sixteenth Vice-President; at the film's end, Ren succeeds Ina as the seventeenth President after the latter resigns.

In 2010, the Star Cinema once again brought the third and the last installment of Ang Tanging Ina film series starring Ai-Ai de las Alas, Eugene Domingo, Marvin Agustin, Nikki Valdez and several others including Jon Avila and Rafael Rosell who are the new cast. The film tells the life of Ina after she quit her position as the President of the Philippines without knowing that she is suffering from brain tumor and very afraid to tell it to her children.

• Ang Tanging Ina (film series)
• Ang Tanging Ina
• Ang Tanging Ina Mo (Last na 'To!)
• Enteng ng Ina Mo

• Official website
• Ang Tanging Ina N'yong Lahat at IMDb