Patel S.I.R

About Patel S.I.R: Patel S.I.R avenges the death of this son's family by going on a killing spree. He vows to kill everyone that was the reason for the death of his son's family before his blinded granddaughter gets her vision back. Why did the villains kill Patel's son in the first place? How a sixty year old Patel does have his revenge?