Sontham is a romantic base movie in which, Vamsy (Aryan Rajesh), Nandu (Namitha) and Bose (Rohit) are buddies since childhood. Vamsy and Nandu are very close to each other. Bose falls in love with a beautiful girl (Neha). When Bose tells about his ladylove to Vamsy, Vamsy brushes it as one more love affair that is bound to fail.
Vamsy feels that friendship is more valuable than love and love spoils the friendship. Nandu, who wanted to express her love, goes back into shelve as she feels Vamsy might get offended.
Vamsy leaves to New Zealand to supervise the overseas operations of his father's company. In New Zealand, he realizes that he is in love with Nandu. When Vamsy return back to India, he finds out that Nandu is already engaged to somebody else.rest of the story is about whether Vamsy express his love to Nandu or not?