Rosy (Meena), a limb and left arm paralysed girl with weak cardiac health, lives at an orphanage (Karunai Illam) along with other orphans that were dumped by their parents forsaking due to disabilities or having no parents and or for other reasons. The fact that she had been disowned by her parents for untold reasons since her birth and her disability to be like other normal children attributes to her rudeness being uncaring and ignorant towards anyone. She even ill treats all her caretakers on the orphanage which turmoils to hatefulness towards her by almost all other orphanage workers and orphan children except the kind mother superior who heads the Karunai Illam. Mother Superior is always kind to everyone and tries to tether the fact of love and affection to everyone regardless of one's age. It is in the beginning of the movie, that is shown that mother superior consults doctors but for what or for whom or why isn't shown. Lalitha (Ambika) arrives to Karunai Illam as a babysitting caretaking woman. She is assigned to take care of rosy by mother superior. She unlike any other caretakers, takes care of rosy despite her rudeness and shows extra care for her like a real mother herself, which even surprises mother superior as the older care takers gave up and sidelined when it came to taking care of rosy owing her arrogance.
It is informed that Rajinikanth, would one day visit the orphanage as a guest to entertain children on a special occasion under the permission of mother superior who thought it would be a good chance to mince change to everyone in the orphanage and would excite the little children. As said, Rajinikanth arrives and every ones gets to their toes as the whole orphanage gets into happiness. Rajinikanth gives a speech and distributes sweets to every little children and staff kindly and everyone receives it with pleasure. But when Rajini's turn came to give rosy some sweets, Rosy as usual emulates her hatred, which turns even bizarre when she smashes Rajini's gifts onto his face. While this infuriates everyone around, even children, Rajini imbibes ignominy caused by the little girl rosy's behaviour, since her being a child and still continues being calm and positive around. To rejuvenate happiness around, announces he will freely showcast his then released new movie Annai Oru Aalayam. Rosy however not only earned everyone's disgust for her act, but on the inside also feels guilty and saddened that she herself did this which even made her more grumpy.
Later that night, loomed over what she did, rosy was as usual stayed isolated from the movie screening happenings around her. But she however got interested in the movie hearing it from her room, that was show cast as promised by Rajinikanth. After glimpse of watching a few scenes of it from far by her far by window and goes on to watch whole movie where in the hero of it, Rajini, saves a baby elephant from poachers and re-unites it with its mother elephant displaying parental love which affects rosy in terms of sentiments that makes her want to apologize for her unkind acts. She next day displays a newer change in her behaviour, to everyone's awe. She apologizes to Rajini sir through a letter, saying that his movie was the reason for her to change her perspective towards her nature which Rajini sir swiftly agrees to and replies her back reciprocating his kindness. Having found herself to have become a bigger fan for Rajinikanth, Rosy obsesses about her favorite superstar-uncle as she would love to call her. Mother superior, happy on this change of Rosy requests to Rajini as this change in metamorphosis of rosy was caused by Rajini sir himself to which Rajinikanth kindly obliges.
Rajini again returns one day and sets up a little drama with K. Bhagyaraj obliging for mother superior's request to please the kids. There he and his young little fan, Rosie bond with each other, which extends to limits where Rajini takes Rosie almost every where, even to his shoots of new movies considering the little child Rosie's love for him as to reciprocate it. One day, while having fun time with Rosie at the illam, in front of Rajini, Rosie coughs up blood then faints. This panics everyone playing around, and soon the doctor is consulted. The doctor comes to become aware that Rosie has a weak heart and she has just a few days left to live, reveals it - and this shocks Lalitha and Rajinikanth himself. Rajini vows to keep his little fan happy for the rest of her life and takes to approach senior doctors for help. While Ambika confronts mother superior in private regarding this, she reveals she was the real mother of Rosie. She had to dump Rosie due to un-natural reasons because of her family and loss of her husband. She interrogates mother superior as to why she didn't tell her about this. Mother superior reveals she was aware of this condition Rosie has had and consulted doctors (shown earlier in the beginning of the movie) earlier than Rosie was even able to speak as a child, only to know the problem was in deeper sense that could not be eradicated by modern medical amenities that only weakens her heart with time being, but only be cured by god and his grace himself.
Knowing that rosie was reaching the edge of her lifetime, mother superior seeks help of Rosy's idol - Rajnikanth, so that she finds solace in him that she remains happy forself, let alone the fact how long she would survive. Rosie demands Rajni once to come and celebrate christmas in an imposter as santa, such that no one realizes. On christmas eve, Rajni does as rosie's wish soon after which he expsoses himself from being a santa to himself. Overcheered, rosie laughs so hard out of happiness, she once again coughed up blood and faints in front of everyone in the middle of a happy occasion. Realizing that night was her last, everyone gathers around crying, especially rosie's friends, who started to like her ever since the change in her attire (After Rajnikanth's arrival) that they were going to miss her forever. On that sad moment, she also reveals, that she was aware that her denmother was no one but her real mother, which make everyone go in shock.
Holding her idol's hand, Rosy dies on Christmas Eve. It is later shown rajnikanth paying tribute to his little fan and he sadly leaves Karunai illam in the memory of the cute little girl that changed because him, Rosie!Rajinikanth as Rajinikanth
Meena as Rosy
Ambika as Lalitha, Mother of Rosy
Rajkumar Sethupathi as Raju, Father of Rosy
Sulakshana as Stella
Jaishankar as himself
Bhagyaraj as himself
Raadhika as herself
Parthiban as K. Bhagyaraj's assistant director
K. Natraj as passport officer
Producer Azhagan Thamizhmani and writer Thooyavan saw a film called Touched by Love (also known as To Elvis, with Love), in 1980 which had Elvis Presley in a guest appearance at a film festival, both got emotional while watching the film which prompted them to attempt a similar story in Tamil. Thooyavan finished writing the screenplay within a month. He wanted to cast M. G. Ramachandran as the hero but could not do so. Thooyavan narrated the story to K. Natraj who was working as one of the assistant directors in Devar Films. Natraj agreed to work on the film and Rajini accepted to act in this film. Rajini initially agreed to give callsheet of 6 days then extended for 10 days since he wanted the film to come out well. The film was entirely shot in a school with 300 students. Rajkumar Sethupathi, brother of actress Latha and husband of actress Sripriya did a small role as Ambika's husband. Meena appeared as one of the main characters. The budget of the film was ₹23 lakhs.
The music composed by Ilaiyaraaja.
On 3 August 1984 The Hindu said, "For one making his debut as director Natraj deserves accolades for the near-to-the-heart treatment of the situations in which the performance of a six-member-group of orphans will make even elder artistes sit up" and concluded, "Babu's camera embellishes the frames". Cinemalead wrote, "Anbulla Rajinikanth made Rajini seal children's heart forever, that was the impact of the movie. The story of a child's emotional bondage with a film actor and her fighting against cancer reached out to audience very well due to Rajini's reach and Meena's acting. The film also gives us some glimpse of Rajini's lifestyle and his real life character". The film ran for 100 days in theatres.