Aaai (English: Hey) is a 2004 Tamil language film starring Sarath Kumar, Namitha, Vadivelu and Kalabhavan Mani. It was a successful film with a good soundtrack.
Velu (R. Sarathkumar) living happily with his sister and friends in Palani. Velu stays away from all wanted trouble and is forced to resort to fighting to defend his sister from the local rowdy (Vincent Asokan).
A flashback follows where it is revealed that Velu is a military officer, and his sister is actually the sister of his best friend (Kalabhavan Mani). It is also revealed that Velu had maintained a low profile to protect his sister from his nemesis (Kota Srinivasa Rao) whom he had left crippled before he went into hiding.
How Velu protects his sister and his love interest Anjali (Namitha) from Kota Srinivasa Rao and Vincent Asokan forms the rest of the story.