The Polanski original is about an angry young woman (Weaver) who's waiting for her husband to come home. He's (Stuart Wilson) late, and returns with a stranger (Kingsley) who gave him a ride home. This stranger turns out to be someone who raped the wife many years ago.
The psychological drama now turns into a cat and mouse game with the stranger being relentlessly cross-examined by the gun-toting wife, with the husband confused on whether to believe his possibly mistaken wife or this extremely articulate stranger.
That's almost exactly the summary given on the Siskiyaan website. The deeper undertones (the man assaulted her repeatedly while she was a political prisoner) have probably been removed, and what remains is a watered-down, barefaced clone.
The recent Dansh, featuring Kay Kay Menon, Sonali Kulkarni and Aditya Shrivastava, had a similar plot as well.