Kaun is a chilling suspense story that keeps you at the edge of your seat till the very end. Urmila Matondkar is a scared girl alone at home. She request to her mother to come home early. She learns from the television set that there is a psycho serial killer absconding and has killed three people. It also said that no one should allow strangers in the home. While this is happening Manoj Bajpai rings the beel and Urmila asks him Kaun? After lots of attepmts and requests he enters the house. Now things start really happening as Urmila's cat is killed after Manoj mentions that he doesn't like cats. Also a third person enters the house who claims to be the inspector. But turned out to be the robber. The serial killer is in the house that's for sure but the question is who is the the serial killer?