This offbeat romantic drama revolves around Venkatadri (Venkatesh), a tough bodyguard who is assigned to protect the family of Varadarajula Naidu (Prakash Raj). Keerthi (Trisha Krishnan) is the college going daughter of Naidu and Venkatadri accompanies her to the college to keep a watch.
Fed up with the close scrutiny maintained by Venkatadri, Keerthi hatches a plan with her friend Swathi (Saloni Aswani) to divert Venkatadri’s attention. Keerthi tries to get away from Venkatedri by calling him from a private number. Venkatadri falls in love with the girl without knowing that it is Keerthi herself.
At one point, Keerthi too feels herself becoming attracted to Venkatadri and expresses her desire to meet him in person. She tells Venkatadri to meet at a railway station and elope with her. Venkatadri agrees, unaware it is Keerthi.
Naidu comes to think that Venkatadri and Keerthi are going to run away. In order to save Venkatadri from Naidu's anger, Keerthi lies that Venkatadri is meeting another girl at the train station. Naidu lets Venkatadri leave as he is desperate but tells his henchmen to kill Venkatadri if a girl does not come there at the station (which implies that Keerthi loves Venkatadri).
Terrified, Keerthi sends Swathi to the station and tells her to tell Venkatadri that she is the lover and that she won't be able to make it to the station. Swathi, seeing Venkatadri, falls in love after all that has happened, and pretends that she is the lover. Keerthi calls her, but Swathi throws the cell phone away, hoping to erase Keerthi from his life completely.
Many years later, after Venkatadri and Swathi's marriage, they have a son. Swathi passes away shortly after. However, before her death, she leaves a diary for her son that outlines the whole story between the phone calls of Venkatadri and Keerthi and their love.
The son later goes to Keerthi's house with Venkatadri to visit an elderly Naidu. Venkatadri is shocked that Keerthi has remained unmarried. The son asks Keerthi to come with him and become his mother and Venkatadri is angry at his son for saying something so blunt and rude. But Naidu begs Venkatadri to take Keerthi as his wife. So they go on to the train together but the son runs away before leaving and throws the diary into a trashcan nearby.
Venkatadri finds the diary and realizes soon that his real lover, the girl who had waited for him for so many years faithfully, was Keerthi. He calls Keerthi on her cell phone and addresses her as Bangaram. Keerthi is overwhelmed with joy and happiness, realizing that Venkatadri has come to know the truth and her identity. She runs toward Venkatadri and they both hug each other while his son is happily watching them.