Ulkuthu story is about Sura Shankar a fishmonger. He wants his sister Kadalarasi to get married to a well-settled guy. He meets Raja, who says that he is the son of a business tycoon and had walked out of the house. Shankar decides to make Raja as his brother-in-law and takes him to his home. While on his stay at the coastal town, Raja has developed enmity with Kaaka Mani. In a situation, he hits Saravanan, son of Kaaka Mani. Sooner, someone murders Saravanan. Who killed Saravanan? Who is Raja and why did he come to the coastal town? Watch the film in theaters.