Ghilli movie is all about Ghilli who is the nickname for the popular state level kabbadi player Velu (Vijay). His father Sivasubramanian (Ashish Vidyarti) is an assistant police commissioner , is a martinet who finds his son (who still has his arrears to clear before he gets his degree) incorrigible. His mother (Janaki Sabesh), on the other hand, dotes on him. His younger sister Bhuvana (`Baby' Jennifer) who is the typical sharp and inquisitive schoolgirl.
Velu goes to Madurai for a kabbadi match. But circumstances force him to lend a helping hand to Dhanalakshmi (Trisha) who is fleeing from the cantankerous Muthupandi (Prakash Raj) who a State Minister's son, madly in love with her. From then on it is a hectic run for the two with Prakashraj and his henchmen, who seem to be teeming all over the place, close on their heels.
Velu hides Danalakshmi in his house and manages to get her a Passport and Visa for America. But Dhanalakshmi is not willing to go to America as she had fallen in love with Velu. Velu and his friends cross many hurdles to get Dhanalaksmi to the Airport in time for the flight before their final league Kabbadi Match, only to find her back in the stadium while the match is going on.
Before she came, Velu had missed her and that caused him to have a lot of trouble playing. The movie ends in a gripping climax with a fight until death between Velu and Muthupandi.