Oyee begins with an establishing shot of a ladies prison. Enter Swetha (Eesha), who is yearning to breathe free from the nauseating atmosphere there. Though she doesn't seem to be someone who has been in a prison for a while, we are given a hint that she has a purpose to leave the place. Then, lady luck smiles on her, as she has been granted parole and comes out of prison to attend her sister's marriage. What made Swetha, who comes across as the quintessential girl-next-door, to commit a crime? This question is left unanswered till the end, though there is a vague mention in a scene of her having murdered someone unintentionally.

The plot kicks in when Swetha meets Krish (Geethan Britto) on a bus. He is on his way to Chennai, to meet his lady love Gayatri (Papri Ghosh). In an unconvincing turn of events, Swetha ends up with Geethan's ancestral necklace, though he remains unaware of this! So, she goes to Krish's village to return the necklace, but his family members mistake her for their soon-to-be daughter-in-law, as they see her wearing the necklace. They are so affectionate towards her and start admiring her beauty and innocence, and do not give her a chance to reveal the truth.

Meanwhile, Krish returns home and tries to convince his relatives that they have mistaken a stranger for Gayatri. But Swetha refutes his claims, and succeeds in making the family believe that she is Gayatri! The director reasons this act of Swetha by saying that she did this out of her attachment with the family, as she was a girl who was deprived of a lovable family since childhood.

Meanwhile, Krish takes up the challenge of participating in a 'silambu' competition posed by another prominent family in the town for the village festival. Whether he saves his family's esteem in the competition, is left for the audience to watch. The unexpected arrival of Gayatri to his home later, and the much-expected love track between Krisha and Swetha, turns the film into a predictable and slightly tiresome triangular love story.

Actors Sangili Murugan and Arjunan, who essay characters who are part of the family, try hard to evoke laughter in several scenes, but in vain. Nagineedu as the head of the family is apt, while Neelima Rani's character as Eesha's sister makes a blink-and-miss appearance. The effort taken by Geethan in learning the basics of silambam deserves mention.

The scenic beauty of the village has been captured well in few scenes by cinematographer Yuga, while fans of maestro Ilaiyaraaja are sure in for a disappointment. The film would have made more sense and could garner a little more attention had the makers produced it with the silambam contest as its core theme.