'Theeya Velai Seiyyanum Kumaru' is a soulful and ebullient romantic comedy that primarily revolves around Kumar's attempts to lose his fear of interacting with members of the opposite sex and finding true love.
Born in a family of loyal enthusiasts of love for generations, Kumar's (Siddharth) luck with love and women has been abysmal ever since he was a toddler. Everyone in the family - starting from the great grandfather, have had love marriages, and this fact not only adds pressure for him to do the same, but elicits frustration at his failure to even take the first step in that direction.
Losing all hope of ever finding love and embarking upon the journey that would end in a happy marriage, Kumar lives life of a loner until he meets Sanjana (Hansika), an attractive co-worker. It is then that Prabhu realises that he wants her at all cost.
Convinced that he doesn't have it in him to impress her, Prabhu seeks the help of a love guru, Mokia (Santhanam). Mokia, in other words, is a broker who fixes up people for a price. How does Mokia help Prabhu to eventually impress Sanjana, and in turn win her heart? This forms the rest of this heart-warming tale of transformation in love.