Plot
Chanthu is a young screenwriter whose mother works in a mansion owned by a man named Thampuran. Thampuran's daughter Indira is in love with Chanthu, who does not love her. After finding out about this, Thampuram forces Chanthu to write love letters to "Vasumathi," an imaginary woman from the fictional "Thottakkattukara" village, and makes sure Indira stumbles upon them. However, unknown to everyone, a real Vasumathi (nicknamed "Suma") exists in a real Thottakkattukara village, where she is about to commit suicide. Upon receiving the letters, Vasumathi begins to expect a savior and starts looking for information about Chanthu. Through the direction of the letters, Vasumathi awaits a departing Chanthu on a bus trip to Madras.
At the bus station, Vasumathi explains her story to dance choreographer Krishnan and several others before Chanthu arrives. During the journey, Vasumathi tries to impress Chanthu, who does not realize who she really is. At Madras, Vasumathi introduces herself as Suma to Chanthu.
Krishnan introduces Chanthu and Vasumathi to his crew's director, Harikrishnan, who allows Chanthu to unfurl his new script. Chanthu opens his own tale to the director and adds that Vasumathi comes out of the home believing those letters. But the director does not accept it, saying that no girl would trust such letters and flee from home like he said, unless she has a strong reason. Seeing the dilemma that Chanthu is facing, Vasumathi helps him and reveals her own origins: she was born in a rich family and was the sole heir of their wealth. One day, her mother Ambika died falling into a well, and Vasumathi's grandmother later died in her sleep, and fingers point to Vasumathi, who was present during those incidents. That, along with her refusal to marry her cousin Aravindan, led Vasumathi to be "exorcised" by a fake Hindu priest. The torture inflicted on Vasumathi, along with her supposed guilt over the recent deaths, is what almost drove her to commit suicide until she received Chanthu's letters. Unknown to Vasumathi, her relatives, led by her uncle Ramu, coveted her inheritance and hired the priest to torture her into committing suicide. Vasumathi's grandfather is the only one in the family who sympathizes with her plight, but he, too, is manipulated into believing that Vasumathi is possessed. The director likes the story and appoints Chanthu as the screenwriter, with Vasumathi joining in to help him.
Later, Krishnan tells the director what is going on, and they try to unite Chanthu and Vasumathi. When Vasumathi decides to show Chanthu the letters, Indira appears, having recently learned about what Thampuran did. Chanthu asks her to leave, but Indira decides to stay in Madras. Days later, Aravindan lures Vasumathi back to Thottakkattukara (per Ramu's orders). Krishnan later reveals the truth about Vasumathi to Chanthu and Indira. Chanthu tries to save Vasumathi from her family, but Aravindan manhandles and sends him back to Madras in disgrace.
Deciding to rectify his mistakes, Chanthu rewrites the script to save Vasumathi. He and the film crew reach the home of Vasumathi's family and scare them using visual effects. They reach Vasumathi and tend to her. Vasumathi's relatives call in the priest to torture Vasumathi again. However, with the film crew's help, Vasumathi burns the priest's beard, and they terrify him with more special effects, making him leave for good. Meanwhile, a remorseful Thampuran arrives to make amends with Chanthu and Indira upon learning what had transpired.
Eventually, the relatives learn that they were tricked. Ramu orders the relatives and their thugs to murder Chanthu and the film crew while he confronts Vasumathi. During the ensuing fight, Ramu admits that it was he who committed the murders to frame Vasumathi. Just as Ramu intends to murder Vasumathi with a sword, Vasumathi's grandfather appears and kills Ramu, having overheard everything Ramu said. Vasumathi reconciles with her grandfather.
With the family's plot exposed, the criminals are arrested. Vasumathi's grandfather entrusts Chanthu and the film crew to take care of her before he is also arrested for killing Ramu. The film crew later makes a movie based on the events, and it is revealed that Chanthu (now a successful screenwriter) married Vasumathi while Indira married Krishnan.
