Dheena story revolves around Dheenadayalan(Ajith) is the 'valarppu' brother of the local dada Adikesavan(Suresh Gopi). He is eternally grateful for this and lives solely to do Adikesavan's bidding, no questions asked.
Dheena learns that his sister(Divya) is in love with a local boy but Adikesavan, who thinks the boy is harassing their sister, goes after him. Things turn tragic when this results in the death of their sister. Deena must now choose between obeying his brother or carrying out his sister's dying wish to protect Chitra, whom he loves, and her family.